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Conic section

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47: 5213: 8865: 5082:). Three types of cones were determined by their vertex angles (measured by twice the angle formed by the hypotenuse and the leg being rotated about in the right triangle). The conic section was then determined by intersecting one of these cones with a plane drawn perpendicular to a generatrix. The type of the conic is determined by the type of cone, that is, by the angle formed at the vertex of the cone: If the angle is acute then the conic is an ellipse; if the angle is right then the conic is a parabola; and if the angle is obtuse then the conic is a hyperbola (but only one branch of the curve). 1792: 1784: 6857: 39: 637: 253: 6141: 31: 382: 7162:) uniquely determine the conic. If another diameter (and its conjugate diameter) are used instead of the major and minor axes of the ellipse, a parallelogram that is not a rectangle is used in the construction, giving the name of the method. The association of lines of the pencils can be extended to obtain other points on the ellipse. The constructions for hyperbolas and parabolas are similar. 5116: 1800: 5149:
commonly used today. Circles, not constructible by the earlier method, are also obtainable in this way. This may account for why Apollonius considered circles a fourth type of conic section, a distinction that is no longer made. Apollonius used the names 'ellipse', 'parabola' and 'hyperbola' for these curves, borrowing the terminology from earlier Pythagorean work on areas.
4985:, there is a unique conic passing through them, which will be non-degenerate; this is true in both the Euclidean plane and its extension, the real projective plane. Indeed, given any five points there is a conic passing through them, but if three of the points are collinear the conic will be degenerate (reducible, because it contains a line), and may not be unique; see 5735: 3065: 5078:). His work did not survive, not even the names he used for these curves, and is only known through secondary accounts. The definition used at that time differs from the one commonly used today. Cones were constructed by rotating a right triangle about one of its legs so the hypotenuse generates the surface of the cone (such a line is called a 316:). It is usually assumed that the cone is a right circular cone for the purpose of easy description, but this is not required; any double cone with some circular cross-section will suffice. Planes that pass through the vertex of the cone will intersect the cone in a point, a line or a pair of intersecting lines. These are called 3263: 7739:
The solutions to a system of two second degree equations in two variables may be viewed as the coordinates of the points of intersection of two generic conic sections. In particular two conics may possess none, two or four possibly coincident intersection points. An efficient method of locating these
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In the real projective plane, a point conic has the property that every line meets it in two points (which may coincide, or may be complex) and any set of points with this property is a point conic. It follows dually that a line conic has two of its lines through every point and any envelope of lines
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a circle will have the focus-directrix property, but it is still not defined by that property. One must be careful in this situation to correctly use the definition of eccentricity as the ratio of the distance of a point on the circle to the focus (length of a radius) to the distance of that point to
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When viewed from the perspective of the complex projective plane, the degenerate cases of a real quadric (i.e., the quadratic equation has real coefficients) can all be considered as a pair of lines, possibly coinciding. The empty set may be the line at infinity considered as a double line, a (real)
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over any division ring, but in particular over either the real or complex numbers, all non-degenerate conics are equivalent, and thus in projective geometry one speaks of "a conic" without specifying a type. That is, there is a projective transformation that will map any non-degenerate conic to any
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that can be stated as: All mirrors in the shape of a non-degenerate conic section reflect light coming from or going toward one focus toward or away from the other focus. In the case of the parabola, the second focus needs to be thought of as infinitely far away, so that the light rays going toward
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The three types of conic sections will reappear in the affine plane obtained by choosing a line of the projective space to be the line at infinity. The three types are then determined by how this line at infinity intersects the conic in the projective space. In the corresponding affine space, one
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are classified at each point as elliptic, parabolic, or hyperbolic, accordingly as their second order terms correspond to an elliptic, parabolic, or hyperbolic quadratic form. The behavior and theory of these different types of PDEs are strikingly different – representative examples is that the
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Another method, based on Steiner's construction and which is useful in engineering applications, is the parallelogram method, where a conic is constructed point by point by means of connecting certain equally spaced points on a horizontal line and a vertical line. Specifically, to construct the
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summarized and greatly extended existing knowledge. Apollonius's study of the properties of these curves made it possible to show that any plane cutting a fixed double cone (two napped), regardless of its angle, will produce a conic according to the earlier definition, leading to the definition
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case of a conic depends on the definition being used and the geometric setting for the conic section. There are some authors who define a conic as a two-dimensional nondegenerate quadric. With this terminology there are no degenerate conics (only degenerate quadrics), but we shall use the more
6106:. Since five points determine a conic, a circle (which may be degenerate) is determined by three points. To obtain the extended Euclidean plane, the absolute line is chosen to be the line at infinity of the Euclidean plane and the absolute points are two special points on that line called the 6550:) as the meet of corresponding rays of two related pencils, it is easy to dualize and obtain the corresponding envelope consisting of the joins of corresponding points of two related ranges (points on a line) on different bases (the lines the points are on). Such an envelope is called a 7341:
points. The intersection possibilities are: four distinct points, two singular points and one double point, two double points, one singular point and one with multiplicity 3, one point with multiplicity 4. If any intersection point has multiplicity > 1, the two curves are said to be
5544: 4379: 7553:, and is thus not normally considered as degenerated. The two lines case occurs when the quadratic expression factors into two linear factors, the zeros of each giving a line. In the case that the factors are the same, the corresponding lines coincide and we refer to the line as a 7307:
in either 2 distinct points (corresponding to two asymptotes) or in 1 double point (corresponding to the axis of a parabola); thus the real hyperbola is a more suggestive real image for the complex ellipse/hyperbola, as it also has 2 (real) intersections with the line at infinity.
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is the semi-major axis defined below.) A parabola may also be defined in terms of its focus and latus rectum line (parallel to the directrix and passing through the focus): it is the locus of points whose distance to the focus plus or minus the distance to the line is equal to
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A circle is a limiting case and is not defined by a focus and directrix in the Euclidean plane. The eccentricity of a circle is defined to be zero and its focus is the center of the circle, but its directrix can only be taken as the line at infinity in the projective plane.
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The classification into elliptic, parabolic, and hyperbolic is pervasive in mathematics, and often divides a field into sharply distinct subfields. The classification mostly arises due to the presence of a quadratic form (in two variables this corresponds to the associated
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Four points in the plane in general linear position determine a unique conic passing through the first three points and having the fourth point as its center. Thus knowing the center is equivalent to knowing two points on the conic for the purpose of determining the curve.
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In the real projective plane, since parallel lines meet at a point on the line at infinity, the parallel line case of the Euclidean plane can be viewed as intersecting lines. However, as the point of intersection is the apex of the cone, the cone itself degenerates to a
3072: 4524: 236:, the apparent difference vanishes: the branches of a hyperbola meet in two points at infinity, making it a single closed curve; and the two ends of a parabola meet to make it a closed curve tangent to the line at infinity. Further extension, by expanding the 5340:
The reflective properties of the conic sections are used in the design of searchlights, radio-telescopes and some optical telescopes. A searchlight uses a parabolic mirror as the reflector, with a bulb at the focus; and a similar construction is used for a
5959: 7440:, when the plane is tangent to the cone (it contains exactly one generator of the cone); or a pair of intersecting lines (two generators of the cone). These correspond respectively to the limiting forms of an ellipse, parabola, and a hyperbola. 3855: 6047:
concepts of Euclidean geometry (concepts concerned with measuring lengths and angles) can not be immediately extended to the real projective plane. They must be redefined (and generalized) in this new geometry. This can be done for arbitrary
5391:) so that all the lines of a parallel class meet on this line. On the other hand, starting with the real projective plane, a Euclidean plane is obtained by distinguishing some line as the line at infinity and removing it and all its points. 8267: 5289:
construction of the conics and then develops the algebraic equations. This work, which uses Fermat's methodology and Descartes' notation has been described as the first textbook on the subject. De Witt invented the term 'directrix'.
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The conic sections have some very similar properties in the Euclidean plane and the reasons for this become clearer when the conics are viewed from the perspective of a larger geometry. The Euclidean plane may be embedded in the
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It has been mentioned that circles in the Euclidean plane can not be defined by the focus-directrix property. However, if one were to consider the line at infinity as the directrix, then by taking the eccentricity to be
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concerns the collinearity of three points that are constructed from a set of six points on any non-degenerate conic. The theorem also holds for degenerate conics consisting of two lines, but in that case it is known as
5730:{\displaystyle \left({\begin{matrix}x&y&z\end{matrix}}\right)\left({\begin{matrix}A&B/2&D/2\\B/2&C&E/2\\D/2&E/2&F\end{matrix}}\right)\left({\begin{matrix}x\\y\\z\end{matrix}}\right)=0.} 3060:{\displaystyle {\begin{pmatrix}x&y\end{pmatrix}}{\begin{pmatrix}A&B/2\\B/2&C\end{pmatrix}}{\begin{pmatrix}x\\y\end{pmatrix}}+{\begin{pmatrix}D&E\end{pmatrix}}{\begin{pmatrix}x\\y\end{pmatrix}}+F=0.} 4221: 346:. The circle is obtained when the cutting plane is parallel to the plane of the generating circle of the cone; for a right cone, this means the cutting plane is perpendicular to the axis. If the cutting plane is 8083:. An oval is a point set that has the following properties, which are held by conics: 1) any line intersects an oval in none, one or two points, 2) at any point of the oval there exists a unique tangent line. 6110:. Lines containing two points with real coordinates do not pass through the circular points at infinity, so in the Euclidean plane a circle, under this definition, is determined by three points that are not 2269: 2121: 3715:
the conic is a parabola and its eccentricity equals 1 (provided it is non-degenerate). Otherwise, assuming the equation represents either a non-degenerate hyperbola or ellipse, the eccentricity is given by
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This has precisely one positive solution—the eccentricity— in the case of a parabola or ellipse, while in the case of a hyperbola it has two positive solutions, one of which is the eccentricity.
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No continuous arc of a conic can be constructed with straightedge and compass. However, there are several straightedge-and-compass constructions for any number of individual points on an arc.
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is an infinitesimally separated pair of lines. A circle of finite radius has an infinitely distant directrix, while a pair of lines of finite separation have an infinitely distant focus.
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In the Euclidean plane, the three types of conic sections appear quite different, but share many properties. By extending the Euclidean plane to include a line at infinity, obtaining a
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on La Palma, in the Canary islands, uses a primary parabolic mirror to reflect light towards a secondary hyperbolic mirror, which reflects it again to a focus behind the first mirror.
4213: 3258:{\displaystyle {\begin{pmatrix}x&y&1\end{pmatrix}}{\begin{pmatrix}A&B/2&D/2\\B/2&C&E/2\\D/2&E/2&F\end{pmatrix}}{\begin{pmatrix}x\\y\\1\end{pmatrix}}=0.} 7856: 4005: 1679: 1285: 5103:. His main interest was in terms of measuring areas and volumes of figures related to the conics and part of this work survives in his book on the solids of revolution of conics, 876: 1019: 4834: 2038: 1714: 1320: 6035: 7547: 6558:
with this property is a line conic. At every point of a point conic there is a unique tangent line, and dually, on every line of a line conic there is a unique point called a
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is again the determinant of the 2 × 2 matrix. In the case of an ellipse the squares of the two semi-axes are given by the denominators in the canonical form.
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is considered to be at rest. If they are bound together, they will both trace out ellipses; if they are moving apart, they will both follow parabolas or hyperbolas. See
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and define a conic to be the set of points whose coordinates satisfy an irreducible quadratic equation in three variables (or equivalently, the zeros of an irreducible
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The black boundaries of the colored regions are conic sections. Not shown is the other half of the hyperbola, which is on the unshown other half of the double cone.
7991: 7303:. Thus there is a 2-way classification: ellipse/hyperbola and parabola. Extending the curves to the complex projective plane, this corresponds to intersecting the 6488: 6440: 6411: 6382: 6354: 6325: 6296: 1500: 1475: 6528: 6228: 1447: 1085: 1063: 1041: 8141: 6464: 6268: 6248: 4776: 2562: 6562:. An important theorem states that the tangent lines of a point conic form a line conic, and dually, the points of contact of a line conic form a point conic. 2666: 342:
is a special kind of ellipse, although historically Apollonius considered it a fourth type. Ellipses arise when the intersection of the cone and plane is a
4849:, a conic section with one focus at the origin and, if any, the other at a negative value (for an ellipse) or a positive value (for a hyperbola) on the 109:
have various distinguishing properties, many of which can be used as alternative definitions. One such property defines a non-circular conic to be the
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As multiplying all six coefficients by the same non-zero scalar yields an equation with the same set of zeros, one can consider conics, represented by
1811:, the focus-directrix property can be used to produce the equations satisfied by the points of the conic section. By means of a change of coordinates ( 707:
is the chord between the two vertices: the longest chord of an ellipse, the shortest chord between the branches of a hyperbola. Its half-length is the
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In two variables quadratic forms are classified by discriminant, analogously to conics, but in higher dimensions the more useful classification is as
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hyperbola, one whose asymptotes are perpendicular, there is an alternative standard form in which the asymptotes are the coordinate axes and the line
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If a conic in the Euclidean plane is being defined by the zeros of a quadratic equation (that is, as a quadric), then the degenerate conics are: the
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intersect each identified line with either one of the two original conics; this step can be done efficiently using the dual conic representation of
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in a projective plane, the dual of each point is a line, and the dual of a locus of points (a set of points satisfying some condition) is called an
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Alternatively, an ellipse can be defined in terms of two focus points, as the locus of points for which the sum of the distances to the two foci is
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and some authors do not consider them to be conics at all. Unless otherwise stated, "conic" in this article will refer to a non-degenerate conic.
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From Alexandria, Through Baghdad: Surveys and Studies in the Ancient Greek and Medieval Islamic Mathematical Sciences in Honor of J.L. Berggren
7179:, ellipses and hyperbolas are not distinct: one may consider a hyperbola as an ellipse with an imaginary axis length. For example, the ellipse 3578:
of the 2 × 2 matrix) are invariant under arbitrary rotations and translations of the coordinate axes, as is the determinant of the
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Wilczynski, E. J. (1916), "Some remarks on the historical development and the future prospects of the differential geometry of plane curves",
8613: 7447:, a point, or a pair of lines which may be parallel, intersect at a point, or coincide. The empty set case may correspond either to a pair of 4374:{\displaystyle {\frac {{\tilde {x}}^{2}}{-S/(\lambda _{1}^{2}\lambda _{2})}}+{\frac {{\tilde {y}}^{2}}{-S/(\lambda _{1}\lambda _{2}^{2})}}=1,} 50:
This diagram clarifies the different angles of the cutting planes that result in the different properties of the three types of conic section.
7719:) in a plane and the system of conics which pass through a fixed set of four points (again in a plane and no three collinear) is called a 8596: 5408:
obtains an ellipse if the conic does not intersect the line at infinity, a parabola if the conic intersects the line at infinity in one
5374:, and the irreducible quadrics in a two dimensional projective space (that is, having three variables) are traditionally called conics. 7584:
To distinguish the degenerate cases from the non-degenerate cases (including the empty set with the latter) using matrix notation, let
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corresponding to the axis, and a hyperbola if the conic intersects the line at infinity in two points corresponding to the asymptotes.
2197: 2049: 10965: 6504:) is uniquely determined by prescribing the images of three lines, for the Steiner generation of a conic section, besides two points 1513: 1119: 288:
The conic sections have been studied for thousands of years and have provided a rich source of interesting and beautiful results in
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every surface can be taken to be globally (at every point) positively curved, flat, or negatively curved. In higher dimensions the
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to the study of conics. This had the effect of reducing the geometrical problems of conics to problems in algebra. However, it was
9645: 7365:. Intersecting with the line at infinity, each conic section has two points at infinity. If these points are real, the curve is a 10337: 8633: 7741: 4662: 2878: 7727:
of the pencil. Through any point other than a base point, there passes a single conic of the pencil. This concept generalizes a
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and this helped to provide impetus for the study of this new field. In particular, Pascal discovered a theorem known as the
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AD) is credited with expounding on the importance of the concept of a conic's focus, and detailing the related concept of a
4519:{\displaystyle {\frac {{\tilde {x}}^{2}}{-S/(\lambda _{1}\Delta )}}+{\frac {{\tilde {y}}^{2}}{-S/(\lambda _{2}\Delta )}}=1,} 7428:
In the Euclidean plane, using the geometric definition, a degenerate case arises when the cutting plane passes through the
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who first defined the conic sections as instances of equations of second degree. Written earlier, but published later,
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only the images of 3 lines have to be given. These 5 items (2 points, 3 lines) uniquely determine the conic section.
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The procedure to locate the intersection points follows these steps, where the conics are represented by matrices:
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Yet another general method uses the polarity property to construct the tangent envelope of a conic (a line conic).
5370:). More technically, the set of points that are zeros of a quadratic form (in any number of variables) is called a 4082: 3267:
This form is a specialization of the homogeneous form used in the more general setting of projective geometry (see
6052:, but to obtain the real projective plane as the extended Euclidean plane, some specific choices have to be made. 2770: 144: 9530: 9257: 8674: 6729:
if the points of intersection of opposite sides of a hexagon are collinear, then the six vertices lie on a conic.
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Mathematical Handbook for Scientists and Engineers: Definitions, Theorems, and Formulas for Reference and Review
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Generalizing the focus properties of conics to the case where there are more than two foci produces sets called
10970: 10891: 10881: 10818: 10213: 8853: 7320:: the non-degenerate conics cannot be distinguished from one another, since any can be taken to any other by a 5049:". This is important for many applications, such as aerodynamics, where a smooth surface is required to ensure 4174: 17: 7812: 1812: 10568: 10131: 8864: 8609: 8127: 7728: 7712: 7140:
projectively but not perspectively. The sought for conic is obtained by this construction since three points
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Apollonius's work was translated into Arabic, and much of his work only survives through the Arabic version.
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The eccentricity of an ellipse can be seen as a measure of how far the ellipse deviates from being circular.
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and the conics may be considered as objects in this projective geometry. One way to do this is to introduce
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of a conic. A point on just one tangent line is on the conic. A point on no tangent line is said to be an
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are polynomial coefficients, in contrast to some sources that denote the semimajor and semiminor axes as
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which correspond to the degenerate conic of the pencil. This can be done by imposing the condition that
2339:-axis only (for the parabola). The rectangular hyperbola, however, is instead symmetric about the lines 1987: 1685: 1291: 11168: 11021: 10659: 8897: 7558: 7334: 6008: 5954:{\displaystyle M=\left({\begin{matrix}A&B&D\\B&C&E\\D&E&F\end{matrix}}\right),} 5346: 450: 386: 125: 7500: 5230: 5212: 11158: 11067: 9475: 9431: 7863: 6356:. Then the intersection points of corresponding lines form a non-degenerate projective conic section. 5099:
BC) is known to have studied conics, having determined the area bounded by a parabola and a chord in
3850:{\displaystyle e={\sqrt {\frac {2{\sqrt {(A-C)^{2}+B^{2}}}}{\eta (A+C)+{\sqrt {(A-C)^{2}+B^{2}}}}}},} 717:). When an ellipse or hyperbola are in standard position as in the equations below, with foci on the 4986: 648:), foci, and directrix, various geometric features and lengths are associated with a conic section. 10980: 10960: 10896: 10813: 10715: 10674: 8936:
The empty set is included as a degenerate conic, since it may arise as a solution of this equation.
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of lines. Using Steiner's definition of a conic (this locus of points will now be referred to as a
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that lies on this line and is on the conic determined by the five points can be constructed. Let
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the eccentricity can be written as a function of the coefficients of the quadratic equation. If
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are interesting objects of study, and have strikingly different properties, as discussed at
8452:(mix of positive and negative but no zeros). This classification underlies many that follow. 806: 501: 11118: 10990: 10649: 9272: 8849: 8523: 8369: 8029: 7999: 7785: 7758: 7228: 6618: 5535: 5342: 5248: 5152: 5075: 4962: 426:
Alternatively, one can define a conic section purely in terms of plane geometry: it is the
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Consider finding the midpoint of a line segment with one endpoint on the line at infinity.
8262:{\displaystyle x_{1}^{2}+x_{2}^{2}+\cdots +x_{k}^{2}-x_{k+1}^{2}-\cdots -x_{k+\ell }^{2},} 7976: 6473: 6416: 6387: 6367: 6330: 6301: 6281: 5869:(or some variation of this) so that the matrix of the conic section has the simpler form, 2646:{\displaystyle (a\sec \theta ,b\tan \theta ),{\text{ or }}(\pm a\cosh \psi ,b\sinh \psi )} 1481: 1456: 593:
are the same as those obtained by planes intersecting a cone is facilitated by the use of
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is the line joining the foci of an ellipse or hyperbola, and its midpoint is the curve's
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Practical Conic Sections: The geometric properties of ellipses, parabolas and hyperbolas
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intersects each conic section twice. If the intersection point is double, the line is a
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to exactly one generating line of the cone, then the conic is unbounded and is called a
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Trilinear Coordinates and Other Methods of Modern Analytical Geometry of Two Dimensions
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the points of intersection will represent the solutions to the initial equation system.
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is a special case of the ellipse, though it was sometimes called as a fourth type. The
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Coxeter and several other authors use the term 'self-conjugate' instead of 'absolute'.
8130:, namely by their positive index, zero index, and negative index: a quadratic form in 3279:
The conic sections described by this equation can be classified in terms of the value
2764:), and all conic sections arise in this way. The most general equation is of the form 10985: 10932: 10803: 10618: 10613: 10497: 10467: 10449: 10419: 10403: 10381: 10361: 10341: 10319: 10312: 10289:
Planar Circle Geometries, an Introduction to Moebius-, Laguerre- and Minkowski Planes
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Perspectives on Projective Geometry: A Guided Tour Through Real and Complex Geometry
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If the determinant of the matrix of the conic section is zero, the conic section is
5254: 5233:", a precursor to the concept of limits. Kepler first used the term 'foci' in 1604. 881:
For conics in standard position, these parameters have the following values, taking
628:; plus if the point is between the directrix and the latus rectum, minus otherwise. 10975: 10861: 10838: 9967: 8618: 7745: 7433: 7415: 7347: 7304: 6571: 6049: 6003: 5400: 5384: 5334: 5236: 5194: 3408: 678: 594: 440: 301: 233: 115: 10500: 9830: 8072:
2, as some formulas can not be used. For example, the matrix representations used
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the directrix (this distance is infinite) which gives the limiting value of zero.
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found applications of the theory, most notably the Persian mathematician and poet
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It can also be shown that the eccentricity is a positive solution of the equation
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describes the infinitesimal geometry, and may at each point be either positive –
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be the determinant of the 3 × 3 matrix of the conic section—that is,
5226: 5183: 4982: 709: 370: 309: 134: 106: 71: 38: 6102:
A conic in a projective plane that contains the two absolute points is called a
5179: 5079: 4071: 10773: 10598: 10583: 10560: 10399: 10307: 9613: 9243: 8364:– positive-definite (the negative is also included), corresponding to ellipses, 8121: 6690: 6672: 5367: 5330: 241: 8962:
This form of the equation does not generalize to fields of characteristic two.
3398:{\displaystyle \left|{\begin{matrix}A&B/2\\B/2&C\end{matrix}}\right|.} 681:
parallel to the directrix and passing through a focus; its half-length is the
11142: 11105: 10886: 10866: 10588: 10520: 10433: 10089: 8626: 8622: 8135: 8065: 7662:
be the discriminant. Then the conic section is non-degenerate if and only if
7437: 7378: 7358: 6713: 6501: 6446:(1-1 correspondence) such that corresponding lines intersect on a fixed line 6275: 6153: 6135: 6055:
Fix an arbitrary line in a projective plane that shall be referred to as the
5258: 5240: 5127:
The greatest progress in the study of conics by the ancient Greeks is due to
4649:{\displaystyle \left({\begin{matrix}A&B/2\\B/2&C\end{matrix}}\right)} 760:
as in the standard equation below. By analogy, for a hyperbola the parameter
415: 10279:
The Universe of Conics: From the ancient Greeks to 21st century developments
5197:
and cubic equations, although his solution did not deal with all the cases.
11052: 11026: 11016: 11006: 10808: 10628: 10149: 9502: 8111: 7362: 6271: 6044: 5409: 5200:
An instrument for drawing conic sections was first described in 1000 AD by
5050: 5012: 4965:; for instance, determining the orbits of objects revolving about the Sun. 3319: 721:-axis and center at the origin, the vertices of the conic have coordinates 343: 607:; while a hyperbola is the locus for which the difference of distances is 369:(intersection of a plane with a sphere, producing a circle or point), and 46: 10927: 10765: 10265: 8677:
as elliptic, parabolic, or hyperbolic accordingly as their half-trace is
8094: 7569:, i.e. with the apex at infinity. Other sections in this case are called 6972:
equal segments and use parallel projection, with respect to the diagonal
5276: 5266: 5070:
It is believed that the first definition of a conic section was given by
3551: 3331: 2862: 1827:-axis as principal axis and the origin (0,0) as center. The vertices are 237: 8277:, is the negative index, and the remaining variables are the zero index 6853:, as many additional points on the conic as desired can be constructed. 5019:(or inner point) of the conic, while a point on two tangent lines is an 229:
The geometric properties of the conic can be deduced from its equation.
10922: 9542: 8478:; infinitesimally, to second order the surface looks like the graph of 8079:
A generalization of a non-degenerate conic in a projective plane is an
6579:
defined a conic as the point set given by all the absolute points of a
6059:. Select two distinct points on the absolute line and refer to them as 5286: 5190: 5089: 5071: 5054: 5046: 4584: 636: 252: 244:
coordinates, provides the means to see this unification algebraically.
137:
of degree 2; that is, as the set of points whose coordinates satisfy a
129:. The type of conic is determined by the value of the eccentricity. In 9304:, Forgotten Books, 2012 (orig. Deighton, Bell, and Co., 1866), p. 203. 10783: 10505: 7716: 7573:. The non-degenerate cylindrical sections are ellipses (or circles). 7444: 7366: 7333:, two conic sections have four points in common (if one accounts for 6608: 6443: 6111: 5318: 5311: 3489: 2554: 1933:. In standard form the parabola will always pass through the origin. 1506: 389:
sharing a focus point and directrix line, including an ellipse (red,
335: 281: 79: 8840:
The variance-to-mean ratio classifies several important families of
7429: 6140: 8946: 7374: 6712:
A von Staudt conic in the real projective plane is equivalent to a
6662: 6583:
that has absolute points. Von Staudt introduced this definition in
5307: 3471: 2494: 1383: 748:
is the shortest diameter of an ellipse, and its half-length is the
331: 274: 113:
of those points whose distances to some particular point, called a
83: 8872:, move left and right over the SVG image to rotate the double cone 7809:, consider the pencil of conics given by their linear combination 7549:
An imaginary ellipse does not satisfy the general definition of a
6727:
One of them is based on the converse of Pascal's theorem, namely,
11095: 11080: 8646: 8322:
In two variables the non-zero quadratic forms are classified as:
7370: 7343: 5747:
Some authors prefer to write the general homogeneous equation as
5371: 5326: 5303: 3427: 2432: 1112: 327: 267: 87: 30: 10407: 7993:. These turn out to be the solutions of a third degree equation. 6709:) of a polarity is one which is incident with its polar (pole). 2264:{\displaystyle {\frac {x^{2}}{a^{2}}}-{\frac {y^{2}}{b^{2}}}=1,} 2116:{\displaystyle {\frac {x^{2}}{a^{2}}}+{\frac {y^{2}}{b^{2}}}=1,} 11075: 10193:
Brannan, David A.; Esplen, Matthew F.; Gray, Jeremy J. (1999),
9538: 8660: 8023:, identify the two, possibly coincident, lines constituting it. 7397: 5299: 5085: 3550:
of the conic section's quadratic equation (or equivalently the
3451: 2370: 1894: 1577:{\displaystyle {\frac {x^{2}}{a^{2}}}-{\frac {y^{2}}{b^{2}}}=1} 1183:{\displaystyle {\frac {x^{2}}{a^{2}}}+{\frac {y^{2}}{b^{2}}}=1} 963: 700:) is the distance from a focus to the corresponding directrix. 381: 339: 260: 91: 4833: 10094:
Geometry Revealed: A Jacob's Ladder to Modern Higher Geometry
7561:
2) and this is the previous case of a tangent cutting plane.
5322: 5298:
For specific applications of each type of conic section, see
5074:(died 320 BC) as part of his solution of the Delian problem ( 2760:
in two variables is always a conic section (though it may be
764:
in the standard equation is also called the semi-minor axis.
498:
If the angle between the surface of the cone and its axis is
373:(intersection of an elliptic cone with a concentric sphere). 362:
halves of the cone, producing two separate unbounded curves.
67: 9242:(Mineola, NY: Dover, 2007). Originally published in 1957 by 6500:
As a projective mapping in a projective plane over a field (
4171:
can be converted to canonical form in transformed variables
2333:-axis (for the circle, ellipse and hyperbola), or about the 418:
circle centered at the focus, and the conic of eccentricity
8064:
Conics may be defined over other fields (that is, in other
5251:
from which many other properties of conics can be deduced.
4961:
The polar form of the equation of a conic is often used in
4748:{\displaystyle \lambda ^{2}-(A+C)\lambda +(AC-(B/2)^{2})=0} 2321:
The first four of these forms are symmetric about both the
1911:. For the parabola, the standard form has the focus on the 10277:
Glaeser, Georg; Stachel, Hellmuth; Odehnal, Boris (2016),
8844:: the constant distribution as circular (eccentricity 0), 7132:. The labeling associates the lines of the pencil through 5000:
points in general position that it passes through and 5 –
1778: 7436:, when the plane intersects the cone only at the apex; a 4996:
Furthermore, a conic is determined by any combination of
10515:
Occurrence of the conics. Conics in nature and elsewhere
9255:
Ayoub, Ayoub B., "The eccentricity of a conic section",
6129: 5383:
is embedded in the real projective plane by adjoining a
3601: 2883:
The above equation can be written in matrix notation as
518:
and the angle between the cutting plane and the axis is
9827:
Jacob Steiner's Vorlesungen über synthetische Geometrie
9590:
A History of Algebra: From al-Khwārizmī to Emmy Noether
8068:). However, some care must be used when the field has 6144:
Definition of the Steiner generation of a conic section
300:
A conic is the curve obtained as the intersection of a
98:
studied conic sections, culminating around 200 BC with
10495: 10448:(Readings in Mathematics), New York: Springer-Verlag, 9567:. Springer Science & Business Media. p. 110. 9471:
Science in Medieval Islam: An Illustrated Introduction
9270:
Ayoub, A. B., "The central conic sections revisited",
8273:
is the positive index, the number of −1 coefficients,
6497:
mapping is a finite sequence of perspective mappings.
5890: 5859:{\displaystyle Ax^{2}+2Bxy+Cy^{2}+2Dxz+2Eyz+Fz^{2}=0,} 5693: 5582: 5553: 5163: 4599: 3345: 3221: 3110: 3081: 3024: 3000: 2971: 2919: 2895: 1954:
is the principal axis. The foci then have coordinates
1823:. For ellipses and hyperbolas a standard form has the 10276: 9592:. Springer Science & Business Media. p. 29. 8788: 8738: 8683: 8553: 8526: 8484: 8401: 8372: 8330: 8287: 8144: 8032: 8002: 7979: 7959: 7898: 7866: 7815: 7788: 7761: 7711:
A (non-degenerate) conic is completely determined by
7503: 7457: 7263: 7231: 7185: 6510: 6476: 6452: 6419: 6390: 6370: 6333: 6304: 6284: 6256: 6236: 6210: 6166: 6011: 5878: 5756: 5547: 5433: 5011:
Any point in the plane is on either zero, one or two
4864: 4837:
Development of the conic section as the eccentricity
4788: 4764: 4665: 4593: 4562: 4535: 4393: 4224: 4177: 4085: 4076:
In the case of an ellipse or hyperbola, the equation
4016: 3884: 3725: 3615: 3339: 3285: 3075: 2889: 2773: 2669: 2565: 2505: 2443: 2381: 2283: 2200: 2135: 2052: 1990: 1723: 1688: 1643: 1591: 1516: 1484: 1459: 1434: 1393: 1329: 1294: 1249: 1197: 1122: 1094: 1072: 1050: 1028: 973: 887: 842: 809: 776: 547: 524: 504: 147: 8858:
cumulants of some discrete probability distributions
6039: 5243:
developed a theory of conics using an early form of
1766:{\displaystyle {\frac {b^{2}}{\sqrt {a^{2}+b^{2}}}}} 1372:{\displaystyle {\frac {b^{2}}{\sqrt {a^{2}-b^{2}}}}} 580:{\displaystyle {\frac {\cos \alpha }{\cos \beta }}.} 376: 10394:Protter, Murray H.; Morrey, Charles B. Jr. (1970), 9190: 9188: 8726:{\displaystyle 0\leq |\operatorname {tr} |/2<1,} 8101:, which shares many properties with planar conics. 7425:traditional terminology and avoid that definition. 7026:label the left-hand endpoints of the segments with 5524:{\displaystyle Ax^{2}+Bxy+Cy^{2}+Dxz+Eyz+Fz^{2}=0.} 3606:When the conic section is written algebraically as 10437: 10311: 10043: 9829:, B. G. Teubner, Leipzig 1867 (from Google Books: 9563:Sidoli, Nathan; Brummelen, Glen Van (2013-10-30). 8824: 8774: 8725: 8579: 8539: 8513: 8427: 8385: 8356: 8314: 8261: 8045: 8015: 7985: 7965: 7945: 7884: 7850: 7801: 7774: 7541: 7485: 7295: 7249: 7217: 7168: 6522: 6482: 6458: 6434: 6405: 6376: 6348: 6319: 6290: 6262: 6242: 6222: 6196: 6029: 5953: 5858: 5729: 5523: 5325:of two massive objects that interact according to 5189:A century before the more famous work of Khayyam, 4977:. Formally, given any five points in the plane in 4903: 4817: 4770: 4747: 4648: 4575: 4548: 4518: 4373: 4207: 4160: 4054: 3999: 3849: 3693: 3564:of the 2 × 2 matrix) and the quantity 3397: 3310: 3257: 3059: 2850: 2730: 2645: 2542: 2482: 2420: 2308: 2263: 2180: 2115: 2032: 1765: 1708: 1673: 1629:{\displaystyle {\sqrt {1+{\frac {b^{2}}{a^{2}}}}}} 1628: 1576: 1494: 1469: 1441: 1419: 1371: 1314: 1279: 1235:{\displaystyle {\sqrt {1-{\frac {b^{2}}{a^{2}}}}}} 1234: 1182: 1100: 1079: 1057: 1035: 1013: 905: 870: 827: 794: 670:) is the distance between the center and a focus. 579: 533: 510: 221: 141:in two variables which can be written in the form 10192: 9986: 9715: 9339: 9285: 9149: 9089: 9077: 9061: 9012: 8126:Quadratic forms over the reals are classified by 3268: 11140: 10125: 9945: 9185: 8104: 7899: 7683:, two parallel lines (possibly coinciding) when 6860:Parallelogram method for constructing an ellipse 4973:Just as two (distinct) points determine a line, 4818:{\displaystyle \Delta =\lambda _{1}\lambda _{2}} 2181:{\displaystyle y^{2}=4ax,{\text{ with }}a>0,} 10466:(fifth ed.), Addison-Wesley, p. 434, 9646:"Apollonius of Perga Conics Books One to Seven" 9562: 7946:{\displaystyle \det(\lambda C_{1}+\mu C_{2})=0} 7432:of the cone. The degenerate conic is either: a 5964:but this notation is not used in this article. 5352: 4904:{\displaystyle r={\frac {l}{1+e\cos \theta }},} 4065: 10550: 10413: 10109: 9699: 9697: 9434:(Cambridge: Cambridge University Press, 2013). 5031:or coming from the second focus are parallel. 4055:{\displaystyle \Delta =AC-{\frac {B^{2}}{4}}.} 3694:{\displaystyle Ax^{2}+Bxy+Cy^{2}+Dx+Ey+F=0,\,} 2483:{\displaystyle (a\cos \theta ,b\sin \theta ),} 2421:{\displaystyle (a\cos \theta ,a\sin \theta ),} 10536: 10393: 9535:Geometry and Algebra in Ancient Civilizations 9194: 9137: 9113: 9101: 8832:mirroring the classification by eccentricity. 8825:{\displaystyle |\operatorname {tr} |/2>1,} 8393:– degenerate, corresponding to parabolas, and 7581:and the other cases as previously mentioned. 7373:; if there is only one double point, it is a 7369:; if they are imaginary conjugates, it is an 5740:The 3 × 3 matrix above is called 5065: 4161:{\displaystyle Ax^{2}+Bxy+Cy^{2}+Dx+Ey+F=0\,} 589:A proof that the above curves defined by the 10479: 10461: 10360:(2nd ed.), Edinburgh: Oliver and Boyd, 9620:(3rd ed.). New York: Springer. p.  9206: 9125: 9049: 8114:), but can also correspond to eccentricity. 7707:Pencil (mathematics) § Pencil of conics 5182:, who found a geometrical method of solving 3069:The general equation can also be written as 2851:{\displaystyle Ax^{2}+Bxy+Cy^{2}+Dx+Ey+F=0,} 222:{\displaystyle Ax^{2}+Bxy+Cy^{2}+Dx+Ey+F=0.} 10462:Thomas, George B.; Finney, Ross L. (1979), 9694: 9165:Math refresher for scientists and engineers 8597:manifolds with constant sectional curvature 8073: 7257:geometrically a complex rotation, yielding 7225:becomes a hyperbola under the substitution 5394: 5280: 5270: 5229:extended the theory of conics through the " 3322:of the equation. Thus, the discriminant is 78:. The three types of conic section are the 10543: 10529: 10484:(Revised ed.), D.C. Heath and Company 10314:A History of Mathematics / An Introduction 9957: 9026:Precalculus: With Unit Circle Trigonometry 8775:{\displaystyle |\operatorname {tr} |/2=1,} 8435:– indefinite, corresponding to hyperbolas. 7734: 6565: 5415: 5045:Non-degenerate conic sections are always " 640:Conic parameters in the case of an ellipse 42:Conic sections visualized with torch light 9971: 9796: 9612: 9588:Waerden, Bartel L. van der (2013-06-29). 8645:Real Möbius transformations (elements of 7451:parallel lines such as with the equation 4656:— that is, the solutions of the equation 4208:{\displaystyle {\tilde {x}},{\tilde {y}}} 4157: 3690: 2743: 1923:and the directrix the line with equation 1491: 1466: 1438: 1416: 1076: 1054: 1032: 1010: 354:. In the remaining case, the figure is a 10373: 10353: 10318:(2nd ed.), Addison Wesley Longman, 10073: 10041: 9894: 9854: 9814: 9763: 9751: 9313: 9232: 9230: 9228: 8863: 7851:{\displaystyle \lambda C_{1}+\mu C_{2}.} 7723:. The four common points are called the 7154:and two tangents (the vertical lines at 6855: 6139: 5211: 5114: 4832: 3454:, which is a special case of an ellipse; 1798: 1790: 1782: 635: 380: 251: 102:'s systematic work on their properties. 45: 37: 29: 10396:College Calculus with Analytic Geometry 10338:The Mathematical Association of America 10240:, Springer Science & Business Media 10235: 10212: 10126:Akopyan, A.V.; Zaslavsky, A.A. (2007). 9882: 9870: 9790: 9587: 9401:The Thirteen Books of Euclid's Elements 9168:, John Wiley and Sons, pp. 44–45, 7742:matrix representation of conic sections 6988:(the lengths of these segments will be 6091:and the absolute line, with respect to 5424:a conic section can be represented as: 2879:Matrix representation of conic sections 1779:Standard forms in Cartesian coordinates 14: 11141: 10966:Clifford's theorem on special divisors 10432: 10331: 9467: 9316:"A gallery of conics by five elements" 9161: 9065: 7117:will be points of the ellipse between 6621:. Thus, a polarity associates a point 5110: 4000:{\displaystyle \Delta e^{4}+e^{2}-=0,} 27:Curve from a cone intersecting a plane 10524: 10496: 10244: 10169: 10148: 10096:(Berlin/Heidelberg: Springer, 2010), 9933: 9921: 9909: 9739: 9727: 9703: 9688: 9455: 9375: 9363: 9351: 9225: 8950: 8856:as hyperbolic. This is elaborated at 8269:where the number of +1 coefficients, 7136:with the lines of the pencil through 6130:Steiner's projective conic definition 5968: 5327:Newton's law of universal gravitation 5123:, in a 9th-century Arabic translation 3602:Eccentricity in terms of coefficients 2761: 1674:{\displaystyle {\sqrt {a^{2}+b^{2}}}} 1280:{\displaystyle {\sqrt {a^{2}-b^{2}}}} 326:There are three types of conics: the 317: 247: 119:, and some particular line, called a 10306: 10285: 10264: 9842: 9802: 9778: 9676: 9443: 9412: 9387: 9000: 7860:identify the homogeneous parameters 7377:. If the points at infinity are the 7010:times the length of the segments on 6611:between the points and the lines of 5261:both applied their newly discovered 5004:lines that are tangent to it, for 0≤ 4828: 4779: 3865: 3579: 2362:These standard forms can be written 871:{\displaystyle \ p+c={\frac {a}{e}}} 264:       10480:Wilson, W.A.; Tracey, J.I. (1925), 7740:solutions exploits the homogeneous 7700: 7409: 5329:are conic sections if their common 3598:are invariant under rotation only. 1014:{\displaystyle x^{2}+y^{2}=a^{2}\,} 631: 123:, are in a fixed ratio, called the 24: 11124:Vector bundles on algebraic curves 11058:Weber's theorem (Algebraic curves) 10655:Hasse's theorem on elliptic curves 10645:Counting points on elliptic curves 10446:Undergraduate Texts in Mathematics 9291: 8842:discrete probability distributions 8595:is a more complicated object, but 8059: 7311:Further unification occurs in the 6002:as points in the five-dimensional 4789: 4498: 4440: 4017: 3982: 3932: 3885: 2872: 2033:{\displaystyle x^{2}+y^{2}=a^{2},} 1819:) these equations can be put into 1709:{\displaystyle {\frac {b^{2}}{a}}} 1315:{\displaystyle {\frac {b^{2}}{a}}} 1095: 25: 11180: 10489: 10270:A Survey of Geometry (Volume One) 10046:A Catalog of Special Plane Curves 7748:which depends on six parameters. 7690:, or two intersecting lines when 7577:point is the intersection of two 6980:, to form equal segments on side 6731:Specifically, given five points, 6040:Projective definition of a circle 6030:{\displaystyle \mathbf {P} ^{5}.} 3872:if that determinant is positive. 644:In addition to the eccentricity ( 377:Eccentricity, focus and directrix 10377:Fundamental Concepts of Geometry 8474:(flat, parabola), or negative – 8444:(all positive or all negative), 8134:variables can be converted to a 8117:Quadratic form classifications: 7542:{\displaystyle x^{2}+y^{2}+1=0.} 7337:), so there are between 1 and 4 7322:projective linear transformation 6908:, first construct the rectangle 6719: 6087:of the point of intersection of 6014: 5317:Conic sections are important in 5272:Tractatus de sectionibus conicis 5169: 4855:-axis, is given by the equation 434:whose distance to a fixed point 10746:Hurwitz's automorphisms theorem 10414:Richter-Gebert, Jürgen (2011). 10119: 10103: 10083: 10067: 10035: 10021: 9992: 9987:Brannan, Esplen & Gray 1999 9980: 9973:10.1090/s0002-9904-1916-02785-6 9951: 9939: 9927: 9915: 9903: 9888: 9876: 9864: 9848: 9836: 9831:(German) Part II follows Part I 9820: 9808: 9784: 9772: 9757: 9745: 9733: 9721: 9716:Brannan, Esplen & Gray 1999 9709: 9682: 9670: 9638: 9606: 9581: 9556: 9524: 9492: 9461: 9449: 9437: 9418: 9406: 9393: 9381: 9369: 9357: 9345: 9340:Brannan, Esplen & Gray 1999 9333: 9307: 9286:Brannan, Esplen & Gray 1999 9279: 9264: 9258:The College Mathematics Journal 9249: 9212: 9200: 9155: 9150:Brannan, Esplen & Gray 1999 9143: 9131: 9119: 9090:Brannan, Esplen & Gray 1999 9078:Brannan, Esplen & Gray 1999 9062:Brannan, Esplen & Gray 1999 9013:Brannan, Esplen & Gray 1999 8974: 8965: 8956: 8939: 8930: 8854:negative binomial distributions 7885:{\displaystyle (\lambda ,\mu )} 7420:What should be considered as a 7169:In the complex projective plane 6577:Karl Georg Christian von Staudt 5742:the matrix of the conic section 5293: 5026:All the conic sections share a 3274: 1875:for a hyperbola. For a circle, 308:, with the surface of a double 10971:Gonality of an algebraic curve 10882:Differential of the first kind 10464:Calculus and Analytic Geometry 10199:, Cambridge University Press, 10029:"MathWorld: Cylindric section" 9107: 9095: 9083: 9071: 9055: 9043: 9018: 9006: 8994: 8801: 8790: 8751: 8740: 8702: 8691: 8610:Partial differential equations 7934: 7902: 7879: 7867: 7715:in general position (no three 7086:. The points of intersection, 6849:. By varying the line through 6533: 6429: 6423: 6400: 6394: 6343: 6337: 6314: 6308: 6191: 6185: 6176: 6170: 4780:3 × 3 matrix above 4736: 4727: 4712: 4700: 4691: 4679: 4501: 4485: 4461: 4443: 4427: 4403: 4356: 4328: 4304: 4286: 4258: 4234: 4199: 4184: 3985: 3967: 3954: 3951: 3935: 3917: 3904: 3901: 3866:3 × 3 matrix above 3816: 3803: 3795: 3783: 3754: 3741: 3580:3 × 3 matrix above 2640: 2607: 2596: 2566: 2534: 2506: 2474: 2444: 2412: 2382: 767:The following relations hold: 133:, a conic may be defined as a 13: 1: 11114:Birkhoff–Grothendieck theorem 10824:Nagata's conjecture on curves 10695:Schoof–Elkies–Atkin algorithm 10569:Five points determine a conic 10132:American Mathematical Society 8987: 8105:In other areas of mathematics 7296:{\displaystyle x^{2}-w^{2}=1} 7218:{\displaystyle x^{2}+y^{2}=1} 6085:projective harmonic conjugate 5156: 5132: 5093: 4975:five points determine a conic 4968: 4944:the graph is an ellipse, for 4936:, the graph is a circle, for 4072:Ellipse § Canonical form 3535: 3426:, the equation represents an 2543:{\displaystyle (at^{2},2at),} 1803:Standard forms of a hyperbola 410:). The conic of eccentricity 295: 10685:Supersingular elliptic curve 10374:Merserve, Bruce E. (1983) , 10176:History of Analytic Geometry 10042:Lawrence, J. Dennis (1972), 9946:Akopyan & Zaslavsky 2007 9403:, Vol. I, Dover, 1956, pg.16 9222:, Dover Publ., 1966, p. 110. 9220:Matrices and Transformations 8634:Eccentricity classifications 8514:{\displaystyle x^{2}+y^{2},} 8315:{\displaystyle k+\ell +m=n.} 7497:, such as with the equation 5404:other non-degenerate conic. 5353:In the real projective plane 4576:{\displaystyle \lambda _{2}} 4549:{\displaystyle \lambda _{1}} 4066:Conversion to canonical form 3506:, the equation represents a 3488:, the equation represents a 3470:, the equation represents a 3450:, the equation represents a 1795:Standard forms of a parabola 1787:Standard forms of an ellipse 659:. A parabola has no center. 96:ancient Greek mathematicians 7: 10892:Riemann's existence theorem 10819:Hilbert's sixteenth problem 10711:Elliptic curve cryptography 10624:Fundamental pair of periods 9618:Mathematics and its history 9515:John Wiley & Sons, Inc. 9261:34(2), March 2003, 116–121. 9104:, pp. 314–328, 585–589 8876: 8580:{\displaystyle x^{2}-y^{2}} 8428:{\displaystyle x^{2}-y^{2}} 8357:{\displaystyle x^{2}+y^{2}} 7996:given the degenerate conic 7744:, i.e. a 3 × 3 6753:and a line passing through 6108:circular points at infinity 3516:In the notation used here, 2750:Cartesian coordinate system 1420:{\displaystyle y^{2}=4ax\,} 10: 11185: 11022:Moduli of algebraic curves 9468:Turner, Howard R. (1997). 9427:Treatise on Conic Sections 8898:Elliptic coordinate system 8128:Sylvester's law of inertia 7704: 7486:{\displaystyle x^{2}+1=0,} 7413: 7060:label the upper endpoints 6569: 6133: 5347:Herschel optical telescope 5297: 5282:Elementa Curvarum Linearum 5101:Quadrature of the Parabola 5066:Menaechmus and early works 5060: 4926:is the semi-latus rectum. 4778:is the determinant of the 4069: 3864:if the determinant of the 2876: 795:{\displaystyle \ \ell =pe} 474:we obtain an ellipse, for 403:), and a hyperbola (blue, 385:Conic sections of varying 105:The conic sections in the 11104: 11066: 11035: 10999: 10948: 10941: 10915: 10847: 10764: 10728: 10703: 10637: 10606: 10597: 10559: 10398:(2nd ed.), Reading: 10272:, Boston: Allyn and Bacon 10238:The Real Projective Plane 9476:University of Texas Press 9195:Protter & Morrey 1970 9138:Protter & Morrey 1970 9114:Protter & Morrey 1970 9102:Protter & Morrey 1970 7396:, the conic section is a 7327:It can be proven that in 6197:{\displaystyle B(U),B(V)} 5207: 5119:Diagram from Apollonius' 3311:{\displaystyle B^{2}-4AC} 2309:{\displaystyle xy=c^{2}.} 444:) is a constant multiple 11154:Euclidean solid geometry 10789:Cayley–Bacharach theorem 10716:Elliptic curve primality 10354:Faulkner, T. E. (1952), 10236:Coxeter, H.S.M. (1993), 9507:A History of Mathematics 9314:Pamfilos, Paris (2014). 9298:Whitworth, William Allen 9207:Wilson & Tracey 1925 9162:Fanchi, John R. (2006), 9126:Wilson & Tracey 1925 9050:Thomas & Finney 1979 8923: 8593:Riemann curvature tensor 7966:{\displaystyle \lambda } 7313:complex projective plane 6598:, of a projective plane 6079:is defined as the point 5395:Intersection at infinity 5138:BC), whose eight-volume 5105:On Conoids and Spheroids 4920:is the eccentricity and 906:{\displaystyle a,b>0} 591:focus-directrix property 534:{\displaystyle \alpha ,} 256:Types of conic sections: 11048:Riemann–Hurwitz formula 11012:Gromov–Witten invariant 10872:Compact Riemann surface 10660:Mazur's torsion theorem 8888:Circumconic and inconic 8883:Confocal conic sections 8093:The intersection of an 8076:require division by 2. 7735:Intersecting two conics 7579:complex conjugate lines 6566:Von Staudt's definition 6204:of lines at two points 5422:homogeneous coordinates 5416:Homogeneous coordinates 5387:(and its corresponding 5364:homogeneous coordinates 5231:principle of continuity 4979:general linear position 2275:Rectangular hyperbola: 1101:{\displaystyle \infty } 454:) of the distance from 358:: the plane intersects 10665:Modular elliptic curve 10332:Kendig, Keith (2005), 9960:Bull. Amer. Math. Soc. 9531:Van der Waerden, B. L. 9218:Pettofrezzo, Anthony, 8873: 8846:binomial distributions 8836:Variance-to-mean ratio 8826: 8776: 8727: 8641:Möbius transformations 8625:is parabolic, and the 8589:uniformization theorem 8581: 8541: 8515: 8429: 8387: 8358: 8316: 8263: 8047: 8017: 7987: 7967: 7947: 7886: 7852: 7803: 7776: 7543: 7487: 7297: 7251: 7219: 6865:ellipse with equation 6861: 6845:at the required point 6524: 6484: 6466:, which is called the 6460: 6436: 6407: 6378: 6350: 6321: 6292: 6264: 6244: 6230:(all lines containing 6224: 6198: 6145: 6031: 5955: 5860: 5731: 5525: 5281: 5271: 5223: 5186:using conic sections. 5176:Islamic mathematicians 5124: 4905: 4842: 4819: 4772: 4749: 4650: 4577: 4550: 4520: 4375: 4209: 4162: 4056: 4001: 3851: 3695: 3399: 3312: 3259: 3061: 2861:with all coefficients 2852: 2744:General Cartesian form 2732: 2647: 2544: 2484: 2422: 2310: 2265: 2182: 2117: 2034: 1804: 1796: 1788: 1767: 1710: 1675: 1630: 1578: 1496: 1471: 1443: 1421: 1373: 1316: 1281: 1236: 1184: 1102: 1081: 1059: 1037: 1015: 907: 872: 829: 828:{\displaystyle \ c=ae} 796: 641: 581: 535: 512: 511:{\displaystyle \beta } 423: 396:), a parabola (green, 285: 223: 51: 43: 35: 10579:Rational normal curve 10245:Downs, J.W. (2003) , 9424:Apollonius of Perga, 9276:66(5), 1993, 322–325. 8908:Parabolic coordinates 8867: 8850:Poisson distributions 8827: 8777: 8728: 8659:or its 2-fold cover, 8582: 8542: 8540:{\displaystyle x^{2}} 8516: 8430: 8388: 8386:{\displaystyle x^{2}} 8359: 8317: 8264: 8048: 8046:{\displaystyle C_{0}} 8018: 8016:{\displaystyle C_{0}} 7988: 7968: 7948: 7887: 7853: 7804: 7802:{\displaystyle C_{2}} 7777: 7775:{\displaystyle C_{1}} 7755:given the two conics 7676:we have a point when 7544: 7488: 7414:Further information: 7298: 7252: 7250:{\displaystyle y=iw,} 7220: 7173:In the complex plane 6859: 6525: 6485: 6470:of the perspectivity 6461: 6437: 6408: 6379: 6351: 6322: 6293: 6265: 6245: 6225: 6199: 6143: 6032: 5956: 5861: 5732: 5526: 5360:real projective plane 5285:starts with Kepler's 5269:in his 1655 treatise 5215: 5193:used conics to solve 5118: 4906: 4836: 4820: 4773: 4750: 4651: 4578: 4551: 4521: 4376: 4210: 4163: 4057: 4002: 3852: 3696: 3508:rectangular hyperbola 3400: 3313: 3260: 3062: 2853: 2733: 2659:Rectangular hyperbola 2648: 2545: 2485: 2423: 2311: 2266: 2183: 2118: 2035: 1809:Cartesian coordinates 1802: 1794: 1786: 1768: 1711: 1676: 1631: 1579: 1497: 1472: 1444: 1422: 1374: 1317: 1282: 1237: 1185: 1103: 1082: 1060: 1038: 1016: 934:linear eccentricity ( 908: 873: 830: 797: 639: 582: 536: 513: 414:in this figure is an 384: 255: 240:coordinates to admit 224: 135:plane algebraic curve 49: 41: 33: 11119:Stable vector bundle 10991:Weil reciprocity law 10981:Riemann–Roch theorem 10961:Brill–Noether theory 10897:Riemann–Roch theorem 10814:Genus–degree formula 10675:Mordell–Weil theorem 10650:Division polynomials 9273:Mathematics Magazine 9181:Section 3.2, page 45 8953:, p.14, footnote 14. 8870:this interactive SVG 8786: 8736: 8681: 8551: 8524: 8482: 8399: 8370: 8328: 8285: 8142: 8030: 8000: 7986:{\displaystyle \mu } 7977: 7957: 7896: 7864: 7813: 7786: 7759: 7501: 7455: 7261: 7229: 7183: 6540:Principle of Duality 6508: 6483:{\displaystyle \pi } 6474: 6450: 6435:{\displaystyle B(V)} 6417: 6406:{\displaystyle B(U)} 6388: 6377:{\displaystyle \pi } 6368: 6349:{\displaystyle B(V)} 6331: 6320:{\displaystyle B(U)} 6302: 6291:{\displaystyle \pi } 6282: 6254: 6234: 6208: 6164: 6009: 5876: 5754: 5545: 5431: 5377:The Euclidean plane 5343:parabolic microphone 5249:hexagrammum mysticum 5153:Pappus of Alexandria 5076:Duplicating the cube 4951:a parabola, and for 4862: 4786: 4762: 4663: 4591: 4560: 4533: 4391: 4222: 4175: 4083: 4014: 3882: 3723: 3613: 3582:. The constant term 3337: 3283: 3073: 2887: 2771: 2667: 2563: 2503: 2441: 2379: 2281: 2198: 2133: 2050: 1988: 1721: 1686: 1641: 1589: 1514: 1495:{\displaystyle 2a\,} 1482: 1470:{\displaystyle 2a\,} 1457: 1432: 1391: 1327: 1292: 1247: 1195: 1120: 1092: 1070: 1048: 1026: 971: 885: 840: 807: 774: 545: 541:the eccentricity is 522: 502: 481:a parabola, and for 145: 11164:Birational geometry 10942:Structure of curves 10834:Quartic plane curve 10756:Hyperelliptic curve 10736:De Franchis theorem 10680:Nagell–Lutz theorem 10440:Projective Geometry 10357:Projective Geometry 10303:(PDF; 891 kB). 10219:Projective Geometry 10110:Richter-Gebert 2011 9998:Korn, G. A., & 9730:, p. 158, Thm 3-5.1 9323:Forum Geometricorum 9034:Thomson Brooks/Cole 8601:sectional curvature 8476:hyperbolic geometry 8255: 8225: 8201: 8177: 8159: 8097:with a sphere is a 6617:that preserves the 6523:{\displaystyle U,V} 6223:{\displaystyle U,V} 5245:projective geometry 5129:Apollonius of Perga 5111:Apollonius of Perga 5028:reflection property 4981:, meaning no three 4355: 4275: 1915:-axis at the point 1861:for an ellipse and 1817:translation of axes 1442:{\displaystyle 1\,} 1080:{\displaystyle a\,} 1058:{\displaystyle 0\,} 1036:{\displaystyle 0\,} 943:semi-latus rectum ( 664:linear eccentricity 100:Apollonius of Perga 10949:Divisors on curves 10741:Faltings's theorem 10690:Schoof's algorithm 10670:Modularity theorem 10498:Weisstein, Eric W. 10281:, Berlin: Springer 10128:Geometry of Conics 10012:Dover Publications 9116:, pp. 290–314 9068:, pp. 86, 141 8913:Quadratic function 8874: 8852:as parabolic, and 8822: 8772: 8723: 8577: 8537: 8511: 8472:Euclidean geometry 8460:Gaussian curvature 8425: 8383: 8354: 8312: 8259: 8235: 8205: 8187: 8163: 8145: 8088:generalized conics 8066:pappian geometries 8043: 8013: 7983: 7963: 7943: 7882: 7848: 7799: 7772: 7571:cylindric sections 7557:line (a line with 7539: 7483: 7357:Furthermore, each 7293: 7247: 7215: 7082:and going towards 7048:and going towards 6960:. Divide the side 6862: 6619:incidence relation 6585:Geometrie der Lage 6520: 6480: 6456: 6432: 6403: 6374: 6346: 6317: 6288: 6260: 6240: 6220: 6194: 6160:Given two pencils 6146: 6027: 5951: 5942: 5856: 5727: 5715: 5682: 5571: 5521: 5389:points at infinity 5224: 5125: 5023:(or outer point). 4987:further discussion 4901: 4843: 4815: 4768: 4745: 4646: 4640: 4573: 4546: 4516: 4371: 4341: 4261: 4205: 4158: 4052: 3997: 3847: 3691: 3395: 3386: 3332:matrix determinant 3308: 3255: 3243: 3210: 3099: 3057: 3039: 3013: 2986: 2960: 2908: 2848: 2758:quadratic equation 2728: 2643: 2540: 2480: 2418: 2306: 2261: 2178: 2113: 2030: 1807:After introducing 1805: 1797: 1789: 1763: 1706: 1671: 1626: 1574: 1492: 1467: 1439: 1417: 1369: 1312: 1277: 1232: 1180: 1098: 1077: 1055: 1033: 1011: 903: 868: 825: 792: 756:), the same value 642: 577: 531: 508: 424: 290:Euclidean geometry 286: 248:Euclidean geometry 219: 139:quadratic equation 52: 44: 36: 11169:Analytic geometry 11136: 11135: 11132: 11131: 11043:Hasse–Witt matrix 10986:Weierstrass point 10933:Smooth completion 10902:Teichmüller space 10804:Cubic plane curve 10724: 10723: 10638:Arithmetic theory 10619:Elliptic integral 10614:Elliptic function 10482:Analytic Geometry 10347:978-0-88385-335-1 10325:978-0-321-01618-8 10286:Hartmann, Erich, 10206:978-0-521-59787-6 10186:978-0-486-43832-0 10163:978-0-486-46627-9 10141:978-0-8218-4323-9 10050:, Dover, p.  9833:) Part II, pg. 96 9631:978-1-4419-6052-8 9599:978-3-642-51599-6 9574:978-3-642-36736-6 9239:Analytical Conics 8621:is elliptic, the 8606:Second order PDEs 8587:. Indeed, by the 8468:elliptic geometry 8448:(some zeros), or 7729:pencil of circles 7495:imaginary ellipse 7449:complex conjugate 7402:complex conjugate 6554:(or dual conic). 6459:{\displaystyle a} 6263:{\displaystyle V} 6243:{\displaystyle U} 6050:projective planes 5263:analytic geometry 5216:Table of conics, 4896: 4847:polar coordinates 4829:Polar coordinates 4771:{\displaystyle S} 4505: 4464: 4447: 4406: 4360: 4307: 4290: 4237: 4202: 4187: 4047: 3842: 3841: 3838: 3776: 3540:The discriminant 2723: 2722: 2705: 2704: where  2692: 2605: 2250: 2223: 2164: 2102: 2075: 1847:by the equations 1776: 1775: 1761: 1760: 1704: 1669: 1624: 1622: 1566: 1539: 1367: 1366: 1310: 1275: 1230: 1228: 1172: 1145: 952:focal parameter ( 866: 845: 812: 779: 683:semi-latus rectum 572: 312:(a cone with two 131:analytic geometry 16:(Redirected from 11176: 11159:Algebraic curves 10976:Jacobian variety 10946: 10945: 10849:Riemann surfaces 10839:Real plane curve 10799:Cramer's paradox 10779:Bézout's theorem 10604: 10603: 10553:algebraic curves 10545: 10538: 10531: 10522: 10521: 10511: 10510: 10485: 10476: 10458: 10443: 10429: 10410: 10390: 10370: 10350: 10328: 10317: 10302: 10301: 10299: 10294: 10282: 10273: 10261: 10241: 10232: 10209: 10189: 10166: 10145: 10113: 10107: 10101: 10087: 10081: 10071: 10065: 10064: 10049: 10039: 10033: 10032: 10025: 10019: 9996: 9990: 9984: 9978: 9976: 9975: 9955: 9949: 9943: 9937: 9931: 9925: 9919: 9913: 9907: 9901: 9892: 9886: 9880: 9874: 9868: 9862: 9852: 9846: 9840: 9834: 9824: 9818: 9812: 9806: 9800: 9794: 9788: 9782: 9776: 9770: 9761: 9755: 9749: 9743: 9737: 9731: 9725: 9719: 9713: 9707: 9701: 9692: 9686: 9680: 9674: 9668: 9667: 9665: 9663: 9657: 9651:. Archived from 9650: 9642: 9636: 9635: 9610: 9604: 9603: 9585: 9579: 9578: 9560: 9554: 9528: 9522: 9496: 9490: 9489: 9465: 9459: 9453: 9447: 9441: 9435: 9422: 9416: 9410: 9404: 9397: 9391: 9385: 9379: 9373: 9367: 9366:, pp. 17–18 9361: 9355: 9354:, pp. 36ff. 9349: 9343: 9337: 9331: 9330: 9320: 9311: 9305: 9295: 9289: 9283: 9277: 9268: 9262: 9253: 9247: 9234: 9223: 9216: 9210: 9204: 9198: 9192: 9183: 9178: 9159: 9153: 9147: 9141: 9135: 9129: 9123: 9117: 9111: 9105: 9099: 9093: 9092:, pp. 11–16 9087: 9081: 9080:, pp. 13–16 9075: 9069: 9059: 9053: 9047: 9041: 9022: 9016: 9010: 9004: 8998: 8981: 8978: 8972: 8969: 8963: 8960: 8954: 8943: 8937: 8934: 8831: 8829: 8828: 8823: 8809: 8804: 8793: 8781: 8779: 8778: 8773: 8759: 8754: 8743: 8732: 8730: 8729: 8724: 8710: 8705: 8694: 8671: 8657: 8619:Poisson equation 8586: 8584: 8583: 8578: 8576: 8575: 8563: 8562: 8546: 8544: 8543: 8538: 8536: 8535: 8520: 8518: 8517: 8512: 8507: 8506: 8494: 8493: 8434: 8432: 8431: 8426: 8424: 8423: 8411: 8410: 8392: 8390: 8389: 8384: 8382: 8381: 8363: 8361: 8360: 8355: 8353: 8352: 8340: 8339: 8321: 8319: 8318: 8313: 8268: 8266: 8265: 8260: 8254: 8249: 8224: 8219: 8200: 8195: 8176: 8171: 8158: 8153: 8052: 8050: 8049: 8044: 8042: 8041: 8022: 8020: 8019: 8014: 8012: 8011: 7992: 7990: 7989: 7984: 7972: 7970: 7969: 7964: 7953:and solving for 7952: 7950: 7949: 7944: 7933: 7932: 7917: 7916: 7891: 7889: 7888: 7883: 7857: 7855: 7854: 7849: 7844: 7843: 7828: 7827: 7808: 7806: 7805: 7800: 7798: 7797: 7781: 7779: 7778: 7773: 7771: 7770: 7746:symmetric matrix 7721:pencil of conics 7701:Pencil of conics 7696: 7689: 7682: 7675: 7668: 7661: 7647: 7646: 7644: 7643: 7640: 7637: 7616: 7614: 7613: 7610: 7607: 7589: 7548: 7546: 7545: 7540: 7526: 7525: 7513: 7512: 7492: 7490: 7489: 7484: 7467: 7466: 7416:Degenerate conic 7410:Degenerate cases 7395: 7387: 7332: 7319: 7305:line at infinity 7302: 7300: 7299: 7294: 7286: 7285: 7273: 7272: 7256: 7254: 7253: 7248: 7224: 7222: 7221: 7216: 7208: 7207: 7195: 7194: 7178: 7161: 7157: 7153: 7149: 7139: 7135: 7131: 7120: 7116: 7105: 7101: 7092: 7085: 7081: 7077: 7068: 7059: 7058: 7051: 7047: 7043: 7034: 7025: 7024: 7017: 7016: 7009: 7008: 7006: 7005: 7000: 6997: 6987: 6986: 6979: 6978: 6971: 6967: 6966: 6959: 6948: 6913: 6907: 6905: 6903: 6902: 6897: 6894: 6885: 6883: 6882: 6877: 6874: 6852: 6848: 6844: 6843: 6836: 6835: 6828: 6824: 6823: 6816: 6815: 6808: 6804: 6803: 6796: 6795: 6788: 6784: 6783: 6776: 6775: 6768: 6764: 6763: 6756: 6752: 6700: 6688: 6682: 6670: 6660: 6646: 6632: 6626: 6616: 6603: 6597: 6572:Von Staudt conic 6560:point of contact 6529: 6527: 6526: 6521: 6489: 6487: 6486: 6481: 6465: 6463: 6462: 6457: 6441: 6439: 6438: 6433: 6412: 6410: 6409: 6404: 6383: 6381: 6380: 6375: 6355: 6353: 6352: 6347: 6326: 6324: 6323: 6318: 6297: 6295: 6294: 6289: 6269: 6267: 6266: 6261: 6249: 6247: 6246: 6241: 6229: 6227: 6226: 6221: 6203: 6201: 6200: 6195: 6124: 6098: 6094: 6090: 6082: 6078: 6075:of line segment 6070: 6066: 6036: 6034: 6033: 6028: 6023: 6022: 6017: 6004:projective space 6001: 5960: 5958: 5957: 5952: 5947: 5943: 5865: 5863: 5862: 5857: 5846: 5845: 5800: 5799: 5769: 5768: 5736: 5734: 5733: 5728: 5720: 5716: 5687: 5683: 5671: 5658: 5643: 5625: 5610: 5597: 5576: 5572: 5530: 5528: 5527: 5522: 5514: 5513: 5474: 5473: 5446: 5445: 5401:projective space 5385:line at infinity 5382: 5345:. The 4.2 meter 5335:two-body problem 5284: 5274: 5237:Girard Desargues 5161: 5158: 5137: 5134: 5098: 5095: 5040:Pappus's theorem 5035:Pascal's theorem 4957: 4950: 4943: 4935: 4925: 4919: 4910: 4908: 4907: 4902: 4897: 4895: 4872: 4854: 4824: 4822: 4821: 4816: 4814: 4813: 4804: 4803: 4777: 4775: 4774: 4769: 4754: 4752: 4751: 4746: 4735: 4734: 4722: 4675: 4674: 4655: 4653: 4652: 4647: 4645: 4641: 4629: 4614: 4582: 4580: 4579: 4574: 4572: 4571: 4555: 4553: 4552: 4547: 4545: 4544: 4525: 4523: 4522: 4517: 4506: 4504: 4497: 4496: 4484: 4472: 4471: 4466: 4465: 4457: 4453: 4448: 4446: 4439: 4438: 4426: 4414: 4413: 4408: 4407: 4399: 4395: 4384:or equivalently 4380: 4378: 4377: 4372: 4361: 4359: 4354: 4349: 4340: 4339: 4327: 4315: 4314: 4309: 4308: 4300: 4296: 4291: 4289: 4285: 4284: 4274: 4269: 4257: 4245: 4244: 4239: 4238: 4230: 4226: 4214: 4212: 4211: 4206: 4204: 4203: 4195: 4189: 4188: 4180: 4167: 4165: 4164: 4159: 4126: 4125: 4098: 4097: 4061: 4059: 4058: 4053: 4048: 4043: 4042: 4033: 4006: 4004: 4003: 3998: 3975: 3974: 3947: 3946: 3925: 3924: 3897: 3896: 3871: 3868:is negative and 3863: 3856: 3854: 3853: 3848: 3843: 3840: 3839: 3837: 3836: 3824: 3823: 3802: 3778: 3777: 3775: 3774: 3762: 3761: 3740: 3734: 3733: 3714: 3700: 3698: 3697: 3692: 3656: 3655: 3628: 3627: 3597: 3587: 3573: 3563: 3549: 3531: 3527: 3523: 3519: 3505: 3487: 3469: 3449: 3442: 3425: 3407:If the conic is 3404: 3402: 3401: 3396: 3391: 3387: 3375: 3360: 3329: 3325: 3317: 3315: 3314: 3309: 3295: 3294: 3264: 3262: 3261: 3256: 3248: 3247: 3215: 3214: 3199: 3186: 3171: 3153: 3138: 3125: 3104: 3103: 3066: 3064: 3063: 3058: 3044: 3043: 3018: 3017: 2991: 2990: 2965: 2964: 2949: 2934: 2913: 2912: 2868: 2857: 2855: 2854: 2849: 2814: 2813: 2786: 2785: 2737: 2735: 2734: 2729: 2724: 2718: 2714: 2706: 2703: 2698: 2694: 2693: 2685: 2652: 2650: 2649: 2644: 2606: 2603: 2549: 2547: 2546: 2541: 2521: 2520: 2489: 2487: 2486: 2481: 2427: 2425: 2424: 2419: 2358: 2348: 2338: 2332: 2326: 2315: 2313: 2312: 2307: 2302: 2301: 2270: 2268: 2267: 2262: 2251: 2249: 2248: 2239: 2238: 2229: 2224: 2222: 2221: 2212: 2211: 2202: 2187: 2185: 2184: 2179: 2165: 2163: with  2162: 2145: 2144: 2122: 2120: 2119: 2114: 2103: 2101: 2100: 2091: 2090: 2081: 2076: 2074: 2073: 2064: 2063: 2054: 2039: 2037: 2036: 2031: 2026: 2025: 2013: 2012: 2000: 1999: 1977: 1965: 1953: 1932: 1922: 1914: 1910: 1891: 1881: 1874: 1860: 1846: 1842: 1834: 1826: 1772: 1770: 1769: 1764: 1762: 1759: 1758: 1746: 1745: 1736: 1735: 1734: 1725: 1715: 1713: 1712: 1707: 1705: 1700: 1699: 1690: 1680: 1678: 1677: 1672: 1670: 1668: 1667: 1655: 1654: 1645: 1635: 1633: 1632: 1627: 1625: 1623: 1621: 1620: 1611: 1610: 1601: 1593: 1583: 1581: 1580: 1575: 1567: 1565: 1564: 1555: 1554: 1545: 1540: 1538: 1537: 1528: 1527: 1518: 1501: 1499: 1498: 1493: 1476: 1474: 1473: 1468: 1448: 1446: 1445: 1440: 1426: 1424: 1423: 1418: 1403: 1402: 1378: 1376: 1375: 1370: 1368: 1365: 1364: 1352: 1351: 1342: 1341: 1340: 1331: 1321: 1319: 1318: 1313: 1311: 1306: 1305: 1296: 1286: 1284: 1283: 1278: 1276: 1274: 1273: 1261: 1260: 1251: 1241: 1239: 1238: 1233: 1231: 1229: 1227: 1226: 1217: 1216: 1207: 1199: 1189: 1187: 1186: 1181: 1173: 1171: 1170: 1161: 1160: 1151: 1146: 1144: 1143: 1134: 1133: 1124: 1107: 1105: 1104: 1099: 1086: 1084: 1083: 1078: 1064: 1062: 1061: 1056: 1042: 1040: 1039: 1034: 1020: 1018: 1017: 1012: 1009: 1008: 996: 995: 983: 982: 957: 948: 939: 930: 916: 915: 912: 910: 909: 904: 877: 875: 874: 869: 867: 859: 843: 834: 832: 831: 826: 810: 801: 799: 798: 793: 777: 763: 759: 755: 740: 736: 728: 720: 716: 699: 688: 669: 647: 632:Conic parameters 627: 619: 613: 606: 595:Dandelin spheres 586: 584: 583: 578: 573: 571: 560: 549: 540: 538: 537: 532: 517: 515: 514: 509: 487: 480: 473: 461: 458:to a fixed line 457: 447: 437: 433: 421: 413: 409: 402: 395: 284: 277: 270: 263: 234:projective plane 228: 226: 225: 220: 188: 187: 160: 159: 70:obtained from a 21: 11184: 11183: 11179: 11178: 11177: 11175: 11174: 11173: 11139: 11138: 11137: 11128: 11100: 11091:Delta invariant 11062: 11031: 10995: 10956:Abel–Jacobi map 10937: 10911: 10907:Torelli theorem 10877:Dessin d'enfant 10857:Belyi's theorem 10843: 10829:Plücker formula 10760: 10751:Hurwitz surface 10720: 10699: 10633: 10607:Analytic theory 10599:Elliptic curves 10593: 10574:Projective line 10561:Rational curves 10555: 10549: 10501:"Conic Section" 10492: 10474: 10456: 10426: 10388: 10368: 10348: 10326: 10308:Katz, Victor J. 10297: 10295: 10292: 10259: 10230: 10214:Coxeter, H.S.M. 10207: 10187: 10164: 10154:Linear Geometry 10142: 10122: 10117: 10116: 10108: 10104: 10088: 10084: 10072: 10068: 10062: 10040: 10036: 10027: 10026: 10022: 9997: 9993: 9985: 9981: 9956: 9952: 9944: 9940: 9932: 9928: 9920: 9916: 9908: 9904: 9893: 9889: 9881: 9877: 9869: 9865: 9853: 9849: 9841: 9837: 9825: 9821: 9813: 9809: 9801: 9797: 9789: 9785: 9777: 9773: 9762: 9758: 9750: 9746: 9738: 9734: 9726: 9722: 9714: 9710: 9702: 9695: 9687: 9683: 9675: 9671: 9661: 9659: 9655: 9648: 9644: 9643: 9639: 9632: 9614:Stillwell, John 9611: 9607: 9600: 9586: 9582: 9575: 9561: 9557: 9547:Springer Verlag 9529: 9525: 9503:Merzbach, U. C. 9497: 9493: 9486: 9466: 9462: 9454: 9450: 9442: 9438: 9423: 9419: 9411: 9407: 9398: 9394: 9386: 9382: 9374: 9370: 9362: 9358: 9350: 9346: 9338: 9334: 9318: 9312: 9308: 9296: 9292: 9284: 9280: 9269: 9265: 9254: 9250: 9235: 9226: 9217: 9213: 9205: 9201: 9193: 9186: 9176: 9160: 9156: 9148: 9144: 9136: 9132: 9124: 9120: 9112: 9108: 9100: 9096: 9088: 9084: 9076: 9072: 9060: 9056: 9048: 9044: 9023: 9019: 9011: 9007: 8999: 8995: 8990: 8985: 8984: 8979: 8975: 8970: 8966: 8961: 8957: 8944: 8940: 8935: 8931: 8926: 8918:Spherical conic 8903:Equidistant set 8893:Director circle 8879: 8848:as elliptical, 8805: 8800: 8789: 8787: 8784: 8783: 8755: 8750: 8739: 8737: 8734: 8733: 8706: 8701: 8690: 8682: 8679: 8678: 8665: 8661: 8651: 8647: 8571: 8567: 8558: 8554: 8552: 8549: 8548: 8531: 8527: 8525: 8522: 8521: 8502: 8498: 8489: 8485: 8483: 8480: 8479: 8419: 8415: 8406: 8402: 8400: 8397: 8396: 8377: 8373: 8371: 8368: 8367: 8348: 8344: 8335: 8331: 8329: 8326: 8325: 8286: 8283: 8282: 8250: 8239: 8220: 8209: 8196: 8191: 8172: 8167: 8154: 8149: 8143: 8140: 8139: 8122:Quadratic forms 8107: 8099:spherical conic 8062: 8060:Generalizations 8037: 8033: 8031: 8028: 8027: 8007: 8003: 8001: 7998: 7997: 7978: 7975: 7974: 7958: 7955: 7954: 7928: 7924: 7912: 7908: 7897: 7894: 7893: 7865: 7862: 7861: 7839: 7835: 7823: 7819: 7814: 7811: 7810: 7793: 7789: 7787: 7784: 7783: 7766: 7762: 7760: 7757: 7756: 7737: 7709: 7703: 7691: 7684: 7677: 7670: 7663: 7649: 7641: 7638: 7625: 7624: 7622: 7611: 7608: 7603: 7602: 7600: 7591: 7585: 7521: 7517: 7508: 7504: 7502: 7499: 7498: 7462: 7458: 7456: 7453: 7452: 7418: 7412: 7389: 7381: 7352:superosculating 7328: 7315: 7281: 7277: 7268: 7264: 7262: 7259: 7258: 7230: 7227: 7226: 7203: 7199: 7190: 7186: 7184: 7181: 7180: 7174: 7171: 7159: 7155: 7151: 7141: 7137: 7133: 7122: 7118: 7107: 7104: 7097: 7095: 7088: 7087: 7083: 7079: 7076: 7070: 7067: 7061: 7054: 7053: 7049: 7045: 7042: 7036: 7033: 7027: 7020: 7019: 7018:). On the side 7012: 7011: 7001: 6998: 6993: 6992: 6990: 6989: 6982: 6981: 6974: 6973: 6969: 6962: 6961: 6950: 6915: 6909: 6898: 6895: 6890: 6889: 6887: 6878: 6875: 6870: 6869: 6867: 6866: 6850: 6846: 6839: 6838: 6831: 6830: 6826: 6819: 6818: 6811: 6810: 6806: 6799: 6798: 6791: 6790: 6786: 6779: 6778: 6771: 6770: 6766: 6759: 6758: 6754: 6732: 6722: 6696: 6684: 6678: 6666: 6648: 6634: 6628: 6622: 6612: 6599: 6595: 6574: 6568: 6536: 6509: 6506: 6505: 6475: 6472: 6471: 6451: 6448: 6447: 6418: 6415: 6414: 6389: 6386: 6385: 6369: 6366: 6365: 6332: 6329: 6328: 6303: 6300: 6299: 6283: 6280: 6279: 6255: 6252: 6251: 6235: 6232: 6231: 6209: 6206: 6205: 6165: 6162: 6161: 6138: 6132: 6119: 6096: 6092: 6088: 6080: 6076: 6068: 6064: 6061:absolute points 6042: 6018: 6013: 6012: 6010: 6007: 6006: 5975: 5941: 5940: 5935: 5930: 5924: 5923: 5918: 5913: 5907: 5906: 5901: 5896: 5889: 5885: 5877: 5874: 5873: 5841: 5837: 5795: 5791: 5764: 5760: 5755: 5752: 5751: 5714: 5713: 5707: 5706: 5700: 5699: 5692: 5688: 5681: 5680: 5675: 5667: 5662: 5654: 5648: 5647: 5639: 5634: 5629: 5621: 5615: 5614: 5606: 5601: 5593: 5588: 5581: 5577: 5570: 5569: 5564: 5559: 5552: 5548: 5546: 5543: 5542: 5509: 5505: 5469: 5465: 5441: 5437: 5432: 5429: 5428: 5418: 5397: 5378: 5355: 5315: 5296: 5227:Johannes Kepler 5210: 5184:cubic equations 5172: 5159: 5135: 5113: 5096: 5068: 5063: 5053:and to prevent 4971: 4952: 4945: 4937: 4930: 4921: 4915: 4876: 4871: 4863: 4860: 4859: 4850: 4831: 4809: 4805: 4799: 4795: 4787: 4784: 4783: 4763: 4760: 4759: 4730: 4726: 4718: 4670: 4666: 4664: 4661: 4660: 4639: 4638: 4633: 4625: 4619: 4618: 4610: 4605: 4598: 4594: 4592: 4589: 4588: 4567: 4563: 4561: 4558: 4557: 4540: 4536: 4534: 4531: 4530: 4492: 4488: 4480: 4473: 4467: 4456: 4455: 4454: 4452: 4434: 4430: 4422: 4415: 4409: 4398: 4397: 4396: 4394: 4392: 4389: 4388: 4350: 4345: 4335: 4331: 4323: 4316: 4310: 4299: 4298: 4297: 4295: 4280: 4276: 4270: 4265: 4253: 4246: 4240: 4229: 4228: 4227: 4225: 4223: 4220: 4219: 4194: 4193: 4179: 4178: 4176: 4173: 4172: 4121: 4117: 4093: 4089: 4084: 4081: 4080: 4074: 4068: 4038: 4034: 4032: 4015: 4012: 4011: 3970: 3966: 3942: 3938: 3920: 3916: 3892: 3888: 3883: 3880: 3879: 3869: 3861: 3832: 3828: 3819: 3815: 3801: 3779: 3770: 3766: 3757: 3753: 3739: 3735: 3732: 3724: 3721: 3720: 3705: 3651: 3647: 3623: 3619: 3614: 3611: 3610: 3604: 3589: 3583: 3565: 3554: 3541: 3538: 3529: 3525: 3521: 3517: 3496: 3478: 3460: 3444: 3434: 3416: 3385: 3384: 3379: 3371: 3365: 3364: 3356: 3351: 3344: 3340: 3338: 3335: 3334: 3327: 3323: 3290: 3286: 3284: 3281: 3280: 3277: 3242: 3241: 3235: 3234: 3228: 3227: 3217: 3216: 3209: 3208: 3203: 3195: 3190: 3182: 3176: 3175: 3167: 3162: 3157: 3149: 3143: 3142: 3134: 3129: 3121: 3116: 3106: 3105: 3098: 3097: 3092: 3087: 3077: 3076: 3074: 3071: 3070: 3038: 3037: 3031: 3030: 3020: 3019: 3012: 3011: 3006: 2996: 2995: 2985: 2984: 2978: 2977: 2967: 2966: 2959: 2958: 2953: 2945: 2939: 2938: 2930: 2925: 2915: 2914: 2907: 2906: 2901: 2891: 2890: 2888: 2885: 2884: 2881: 2875: 2873:Matrix notation 2866: 2809: 2805: 2781: 2777: 2772: 2769: 2768: 2746: 2713: 2702: 2684: 2674: 2670: 2668: 2665: 2664: 2602: 2564: 2561: 2560: 2516: 2512: 2504: 2501: 2500: 2442: 2439: 2438: 2380: 2377: 2376: 2350: 2340: 2334: 2328: 2322: 2297: 2293: 2282: 2279: 2278: 2244: 2240: 2234: 2230: 2228: 2217: 2213: 2207: 2203: 2201: 2199: 2196: 2195: 2161: 2140: 2136: 2134: 2131: 2130: 2096: 2092: 2086: 2082: 2080: 2069: 2065: 2059: 2055: 2053: 2051: 2048: 2047: 2021: 2017: 2008: 2004: 1995: 1991: 1989: 1986: 1985: 1967: 1955: 1945: 1924: 1916: 1912: 1898: 1883: 1876: 1862: 1848: 1844: 1836: 1828: 1824: 1781: 1754: 1750: 1741: 1737: 1730: 1726: 1724: 1722: 1719: 1718: 1695: 1691: 1689: 1687: 1684: 1683: 1663: 1659: 1650: 1646: 1644: 1642: 1639: 1638: 1616: 1612: 1606: 1602: 1600: 1592: 1590: 1587: 1586: 1560: 1556: 1550: 1546: 1544: 1533: 1529: 1523: 1519: 1517: 1515: 1512: 1511: 1483: 1480: 1479: 1458: 1455: 1454: 1433: 1430: 1429: 1398: 1394: 1392: 1389: 1388: 1360: 1356: 1347: 1343: 1336: 1332: 1330: 1328: 1325: 1324: 1301: 1297: 1295: 1293: 1290: 1289: 1269: 1265: 1256: 1252: 1250: 1248: 1245: 1244: 1222: 1218: 1212: 1208: 1206: 1198: 1196: 1193: 1192: 1166: 1162: 1156: 1152: 1150: 1139: 1135: 1129: 1125: 1123: 1121: 1118: 1117: 1093: 1090: 1089: 1071: 1068: 1067: 1049: 1046: 1045: 1027: 1024: 1023: 1004: 1000: 991: 987: 978: 974: 972: 969: 968: 953: 944: 935: 926: 886: 883: 882: 858: 841: 838: 837: 808: 805: 804: 775: 772: 771: 761: 757: 753: 750:semi-minor axis 738: 730: 722: 718: 714: 710:semi-major axis 697: 694:focal parameter 686: 667: 645: 634: 622: 615: 608: 601: 561: 550: 548: 546: 543: 542: 523: 520: 519: 503: 500: 499: 482: 475: 467: 459: 455: 445: 435: 431: 419: 411: 404: 397: 390: 379: 371:spherical conic 367:spheric section 298: 279: 272: 271: 265: 258: 257: 250: 183: 179: 155: 151: 146: 143: 142: 107:Euclidean plane 74:intersecting a 64:quadratic curve 28: 23: 22: 15: 12: 11: 5: 11182: 11172: 11171: 11166: 11161: 11156: 11151: 11149:Conic sections 11134: 11133: 11130: 11129: 11127: 11126: 11121: 11116: 11110: 11108: 11106:Vector bundles 11102: 11101: 11099: 11098: 11093: 11088: 11083: 11078: 11072: 11070: 11064: 11063: 11061: 11060: 11055: 11050: 11045: 11039: 11037: 11033: 11032: 11030: 11029: 11024: 11019: 11014: 11009: 11003: 11001: 10997: 10996: 10994: 10993: 10988: 10983: 10978: 10973: 10968: 10963: 10958: 10952: 10950: 10943: 10939: 10938: 10936: 10935: 10930: 10925: 10919: 10917: 10913: 10912: 10910: 10909: 10904: 10899: 10894: 10889: 10884: 10879: 10874: 10869: 10864: 10859: 10853: 10851: 10845: 10844: 10842: 10841: 10836: 10831: 10826: 10821: 10816: 10811: 10806: 10801: 10796: 10791: 10786: 10781: 10776: 10770: 10768: 10762: 10761: 10759: 10758: 10753: 10748: 10743: 10738: 10732: 10730: 10726: 10725: 10722: 10721: 10719: 10718: 10713: 10707: 10705: 10701: 10700: 10698: 10697: 10692: 10687: 10682: 10677: 10672: 10667: 10662: 10657: 10652: 10647: 10641: 10639: 10635: 10634: 10632: 10631: 10626: 10621: 10616: 10610: 10608: 10601: 10595: 10594: 10592: 10591: 10586: 10584:Riemann sphere 10581: 10576: 10571: 10565: 10563: 10557: 10556: 10548: 10547: 10540: 10533: 10525: 10519: 10518: 10512: 10491: 10490:External links 10488: 10487: 10486: 10477: 10472: 10459: 10454: 10434:Samuel, Pierre 10430: 10424: 10411: 10400:Addison-Wesley 10391: 10386: 10371: 10366: 10351: 10346: 10329: 10324: 10304: 10283: 10274: 10262: 10257: 10242: 10233: 10228: 10210: 10205: 10190: 10185: 10171:Boyer, Carl B. 10167: 10162: 10146: 10140: 10121: 10118: 10115: 10114: 10102: 10082: 10066: 10060: 10034: 10020: 9991: 9979: 9966:(7): 317–329, 9950: 9938: 9926: 9914: 9902: 9887: 9875: 9863: 9847: 9835: 9819: 9807: 9795: 9783: 9771: 9756: 9744: 9732: 9720: 9708: 9706:, p. 114. 9693: 9691:, p. 110. 9681: 9679:, p. 126. 9669: 9658:on 17 May 2013 9637: 9630: 9605: 9598: 9580: 9573: 9555: 9523: 9491: 9484: 9478:. p. 53. 9460: 9448: 9436: 9417: 9405: 9392: 9380: 9368: 9356: 9344: 9332: 9306: 9290: 9278: 9263: 9248: 9224: 9211: 9199: 9184: 9174: 9154: 9142: 9130: 9118: 9106: 9094: 9082: 9070: 9064:, p. 19; 9054: 9042: 9017: 9005: 8992: 8991: 8989: 8986: 8983: 8982: 8973: 8964: 8955: 8938: 8928: 8927: 8925: 8922: 8921: 8920: 8915: 8910: 8905: 8900: 8895: 8890: 8885: 8878: 8875: 8862: 8861: 8838: 8833: 8821: 8818: 8815: 8812: 8808: 8803: 8799: 8796: 8792: 8771: 8768: 8765: 8762: 8758: 8753: 8749: 8746: 8742: 8722: 8719: 8716: 8713: 8709: 8704: 8700: 8697: 8693: 8689: 8686: 8663: 8649: 8643: 8631: 8630: 8629:is hyperbolic. 8607: 8604: 8574: 8570: 8566: 8561: 8557: 8534: 8530: 8510: 8505: 8501: 8497: 8492: 8488: 8456: 8453: 8438: 8437: 8436: 8422: 8418: 8414: 8409: 8405: 8394: 8380: 8376: 8365: 8351: 8347: 8343: 8338: 8334: 8311: 8308: 8305: 8302: 8299: 8296: 8293: 8290: 8258: 8253: 8248: 8245: 8242: 8238: 8234: 8231: 8228: 8223: 8218: 8215: 8212: 8208: 8204: 8199: 8194: 8190: 8186: 8183: 8180: 8175: 8170: 8166: 8162: 8157: 8152: 8148: 8124: 8106: 8103: 8070:characteristic 8061: 8058: 8057: 8056: 8053: 8040: 8036: 8024: 8010: 8006: 7994: 7982: 7962: 7942: 7939: 7936: 7931: 7927: 7923: 7920: 7915: 7911: 7907: 7904: 7901: 7881: 7878: 7875: 7872: 7869: 7858: 7847: 7842: 7838: 7834: 7831: 7826: 7822: 7818: 7796: 7792: 7769: 7765: 7736: 7733: 7705:Main article: 7702: 7699: 7538: 7535: 7532: 7529: 7524: 7520: 7516: 7511: 7507: 7482: 7479: 7476: 7473: 7470: 7465: 7461: 7411: 7408: 7292: 7289: 7284: 7280: 7276: 7271: 7267: 7246: 7243: 7240: 7237: 7234: 7214: 7211: 7206: 7202: 7198: 7193: 7189: 7170: 7167: 7102: 7093: 7074: 7065: 7052:. On the side 7040: 7031: 6914:with vertices 6721: 6718: 6703:absolute point 6671:is called the 6570:Main article: 6567: 6564: 6535: 6532: 6519: 6516: 6513: 6479: 6455: 6431: 6428: 6425: 6422: 6413:onto a pencil 6402: 6399: 6396: 6393: 6373: 6358: 6357: 6345: 6342: 6339: 6336: 6316: 6313: 6310: 6307: 6287: 6259: 6239: 6219: 6216: 6213: 6193: 6190: 6187: 6184: 6181: 6178: 6175: 6172: 6169: 6134:Main article: 6131: 6128: 6041: 6038: 6026: 6021: 6016: 5962: 5961: 5950: 5946: 5939: 5936: 5934: 5931: 5929: 5926: 5925: 5922: 5919: 5917: 5914: 5912: 5909: 5908: 5905: 5902: 5900: 5897: 5895: 5892: 5891: 5888: 5884: 5881: 5867: 5866: 5855: 5852: 5849: 5844: 5840: 5836: 5833: 5830: 5827: 5824: 5821: 5818: 5815: 5812: 5809: 5806: 5803: 5798: 5794: 5790: 5787: 5784: 5781: 5778: 5775: 5772: 5767: 5763: 5759: 5738: 5737: 5726: 5723: 5719: 5712: 5709: 5708: 5705: 5702: 5701: 5698: 5695: 5694: 5691: 5686: 5679: 5676: 5674: 5670: 5666: 5663: 5661: 5657: 5653: 5650: 5649: 5646: 5642: 5638: 5635: 5633: 5630: 5628: 5624: 5620: 5617: 5616: 5613: 5609: 5605: 5602: 5600: 5596: 5592: 5589: 5587: 5584: 5583: 5580: 5575: 5568: 5565: 5563: 5560: 5558: 5555: 5554: 5551: 5532: 5531: 5520: 5517: 5512: 5508: 5504: 5501: 5498: 5495: 5492: 5489: 5486: 5483: 5480: 5477: 5472: 5468: 5464: 5461: 5458: 5455: 5452: 5449: 5444: 5440: 5436: 5417: 5414: 5396: 5393: 5368:quadratic form 5354: 5351: 5331:center of mass 5295: 5292: 5255:René Descartes 5209: 5206: 5171: 5168: 5141:Conic Sections 5112: 5109: 5067: 5064: 5062: 5059: 5021:exterior point 5017:interior point 4970: 4967: 4929:As above, for 4912: 4911: 4900: 4894: 4891: 4888: 4885: 4882: 4879: 4875: 4870: 4867: 4830: 4827: 4812: 4808: 4802: 4798: 4794: 4791: 4767: 4756: 4755: 4744: 4741: 4738: 4733: 4729: 4725: 4721: 4717: 4714: 4711: 4708: 4705: 4702: 4699: 4696: 4693: 4690: 4687: 4684: 4681: 4678: 4673: 4669: 4644: 4637: 4634: 4632: 4628: 4624: 4621: 4620: 4617: 4613: 4609: 4606: 4604: 4601: 4600: 4597: 4587:of the matrix 4570: 4566: 4543: 4539: 4527: 4526: 4515: 4512: 4509: 4503: 4500: 4495: 4491: 4487: 4483: 4479: 4476: 4470: 4463: 4460: 4451: 4445: 4442: 4437: 4433: 4429: 4425: 4421: 4418: 4412: 4405: 4402: 4382: 4381: 4370: 4367: 4364: 4358: 4353: 4348: 4344: 4338: 4334: 4330: 4326: 4322: 4319: 4313: 4306: 4303: 4294: 4288: 4283: 4279: 4273: 4268: 4264: 4260: 4256: 4252: 4249: 4243: 4236: 4233: 4201: 4198: 4192: 4186: 4183: 4169: 4168: 4156: 4153: 4150: 4147: 4144: 4141: 4138: 4135: 4132: 4129: 4124: 4120: 4116: 4113: 4110: 4107: 4104: 4101: 4096: 4092: 4088: 4067: 4064: 4051: 4046: 4041: 4037: 4031: 4028: 4025: 4022: 4019: 4008: 4007: 3996: 3993: 3990: 3987: 3984: 3981: 3978: 3973: 3969: 3965: 3962: 3959: 3956: 3953: 3950: 3945: 3941: 3937: 3934: 3931: 3928: 3923: 3919: 3915: 3912: 3909: 3906: 3903: 3900: 3895: 3891: 3887: 3858: 3857: 3846: 3835: 3831: 3827: 3822: 3818: 3814: 3811: 3808: 3805: 3800: 3797: 3794: 3791: 3788: 3785: 3782: 3773: 3769: 3765: 3760: 3756: 3752: 3749: 3746: 3743: 3738: 3731: 3728: 3702: 3701: 3689: 3686: 3683: 3680: 3677: 3674: 3671: 3668: 3665: 3662: 3659: 3654: 3650: 3646: 3643: 3640: 3637: 3634: 3631: 3626: 3622: 3618: 3603: 3600: 3537: 3534: 3514: 3513: 3512: 3511: 3475: 3457: 3456: 3455: 3409:non-degenerate 3394: 3390: 3383: 3380: 3378: 3374: 3370: 3367: 3366: 3363: 3359: 3355: 3352: 3350: 3347: 3346: 3343: 3307: 3304: 3301: 3298: 3293: 3289: 3276: 3273: 3254: 3251: 3246: 3240: 3237: 3236: 3233: 3230: 3229: 3226: 3223: 3222: 3220: 3213: 3207: 3204: 3202: 3198: 3194: 3191: 3189: 3185: 3181: 3178: 3177: 3174: 3170: 3166: 3163: 3161: 3158: 3156: 3152: 3148: 3145: 3144: 3141: 3137: 3133: 3130: 3128: 3124: 3120: 3117: 3115: 3112: 3111: 3109: 3102: 3096: 3093: 3091: 3088: 3086: 3083: 3082: 3080: 3056: 3053: 3050: 3047: 3042: 3036: 3033: 3032: 3029: 3026: 3025: 3023: 3016: 3010: 3007: 3005: 3002: 3001: 2999: 2994: 2989: 2983: 2980: 2979: 2976: 2973: 2972: 2970: 2963: 2957: 2954: 2952: 2948: 2944: 2941: 2940: 2937: 2933: 2929: 2926: 2924: 2921: 2920: 2918: 2911: 2905: 2902: 2900: 2897: 2896: 2894: 2877:Main article: 2874: 2871: 2869:not all zero. 2859: 2858: 2847: 2844: 2841: 2838: 2835: 2832: 2829: 2826: 2823: 2820: 2817: 2812: 2808: 2804: 2801: 2798: 2795: 2792: 2789: 2784: 2780: 2776: 2745: 2742: 2741: 2740: 2739: 2738: 2727: 2721: 2717: 2712: 2709: 2701: 2697: 2691: 2688: 2683: 2680: 2677: 2673: 2656: 2655: 2654: 2642: 2639: 2636: 2633: 2630: 2627: 2624: 2621: 2618: 2615: 2612: 2609: 2604: or  2601: 2598: 2595: 2592: 2589: 2586: 2583: 2580: 2577: 2574: 2571: 2568: 2552: 2551: 2550: 2539: 2536: 2533: 2530: 2527: 2524: 2519: 2515: 2511: 2508: 2492: 2491: 2490: 2479: 2476: 2473: 2470: 2467: 2464: 2461: 2458: 2455: 2452: 2449: 2446: 2430: 2429: 2428: 2417: 2414: 2411: 2408: 2405: 2402: 2399: 2396: 2393: 2390: 2387: 2384: 2364:parametrically 2319: 2318: 2317: 2316: 2305: 2300: 2296: 2292: 2289: 2286: 2273: 2272: 2271: 2260: 2257: 2254: 2247: 2243: 2237: 2233: 2227: 2220: 2216: 2210: 2206: 2190: 2189: 2188: 2177: 2174: 2171: 2168: 2160: 2157: 2154: 2151: 2148: 2143: 2139: 2125: 2124: 2123: 2112: 2109: 2106: 2099: 2095: 2089: 2085: 2079: 2072: 2068: 2062: 2058: 2042: 2041: 2040: 2029: 2024: 2020: 2016: 2011: 2007: 2003: 1998: 1994: 1821:standard forms 1780: 1777: 1774: 1773: 1757: 1753: 1749: 1744: 1740: 1733: 1729: 1716: 1703: 1698: 1694: 1681: 1666: 1662: 1658: 1653: 1649: 1636: 1619: 1615: 1609: 1605: 1599: 1596: 1584: 1573: 1570: 1563: 1559: 1553: 1549: 1543: 1536: 1532: 1526: 1522: 1509: 1503: 1502: 1490: 1487: 1477: 1465: 1462: 1452: 1449: 1437: 1427: 1415: 1412: 1409: 1406: 1401: 1397: 1386: 1380: 1379: 1363: 1359: 1355: 1350: 1346: 1339: 1335: 1322: 1309: 1304: 1300: 1287: 1272: 1268: 1264: 1259: 1255: 1242: 1225: 1221: 1215: 1211: 1205: 1202: 1190: 1179: 1176: 1169: 1165: 1159: 1155: 1149: 1142: 1138: 1132: 1128: 1115: 1109: 1108: 1097: 1087: 1075: 1065: 1053: 1043: 1031: 1021: 1007: 1003: 999: 994: 990: 986: 981: 977: 966: 960: 959: 950: 941: 932: 925:eccentricity ( 923: 920: 919:conic section 902: 899: 896: 893: 890: 879: 878: 865: 862: 857: 854: 851: 848: 835: 824: 821: 818: 815: 802: 791: 788: 785: 782: 741:non-negative. 653:principal axis 633: 630: 576: 570: 567: 564: 559: 556: 553: 530: 527: 507: 430:of all points 378: 375: 297: 294: 249: 246: 218: 215: 212: 209: 206: 203: 200: 197: 194: 191: 186: 182: 178: 175: 172: 169: 166: 163: 158: 154: 150: 72:cone's surface 26: 18:Conic sections 9: 6: 4: 3: 2: 11181: 11170: 11167: 11165: 11162: 11160: 11157: 11155: 11152: 11150: 11147: 11146: 11144: 11125: 11122: 11120: 11117: 11115: 11112: 11111: 11109: 11107: 11103: 11097: 11094: 11092: 11089: 11087: 11084: 11082: 11079: 11077: 11074: 11073: 11071: 11069: 11068:Singularities 11065: 11059: 11056: 11054: 11051: 11049: 11046: 11044: 11041: 11040: 11038: 11034: 11028: 11025: 11023: 11020: 11018: 11015: 11013: 11010: 11008: 11005: 11004: 11002: 10998: 10992: 10989: 10987: 10984: 10982: 10979: 10977: 10974: 10972: 10969: 10967: 10964: 10962: 10959: 10957: 10954: 10953: 10951: 10947: 10944: 10940: 10934: 10931: 10929: 10926: 10924: 10921: 10920: 10918: 10916:Constructions 10914: 10908: 10905: 10903: 10900: 10898: 10895: 10893: 10890: 10888: 10887:Klein quartic 10885: 10883: 10880: 10878: 10875: 10873: 10870: 10868: 10867:Bolza surface 10865: 10863: 10862:Bring's curve 10860: 10858: 10855: 10854: 10852: 10850: 10846: 10840: 10837: 10835: 10832: 10830: 10827: 10825: 10822: 10820: 10817: 10815: 10812: 10810: 10807: 10805: 10802: 10800: 10797: 10795: 10794:Conic section 10792: 10790: 10787: 10785: 10782: 10780: 10777: 10775: 10774:AF+BG theorem 10772: 10771: 10769: 10767: 10763: 10757: 10754: 10752: 10749: 10747: 10744: 10742: 10739: 10737: 10734: 10733: 10731: 10727: 10717: 10714: 10712: 10709: 10708: 10706: 10702: 10696: 10693: 10691: 10688: 10686: 10683: 10681: 10678: 10676: 10673: 10671: 10668: 10666: 10663: 10661: 10658: 10656: 10653: 10651: 10648: 10646: 10643: 10642: 10640: 10636: 10630: 10627: 10625: 10622: 10620: 10617: 10615: 10612: 10611: 10609: 10605: 10602: 10600: 10596: 10590: 10589:Twisted cubic 10587: 10585: 10582: 10580: 10577: 10575: 10572: 10570: 10567: 10566: 10564: 10562: 10558: 10554: 10546: 10541: 10539: 10534: 10532: 10527: 10526: 10523: 10516: 10513: 10508: 10507: 10502: 10499: 10494: 10493: 10483: 10478: 10475: 10473:0-201-07540-7 10469: 10465: 10460: 10457: 10455:0-387-96752-4 10451: 10447: 10442: 10441: 10435: 10431: 10427: 10425:9783642172854 10421: 10417: 10412: 10409: 10405: 10401: 10397: 10392: 10389: 10387:0-486-63415-9 10383: 10379: 10378: 10372: 10369: 10367:9780486154893 10363: 10359: 10358: 10352: 10349: 10343: 10339: 10335: 10330: 10327: 10321: 10316: 10315: 10309: 10305: 10291: 10290: 10284: 10280: 10275: 10271: 10267: 10263: 10260: 10258:0-486-42876-1 10254: 10250: 10249: 10243: 10239: 10234: 10231: 10229:9780387406237 10225: 10222:, Blaisdell, 10221: 10220: 10215: 10211: 10208: 10202: 10198: 10197: 10191: 10188: 10182: 10178: 10177: 10172: 10168: 10165: 10159: 10155: 10151: 10150:Artzy, Rafael 10147: 10143: 10137: 10133: 10129: 10124: 10123: 10112:, p. 196 10111: 10106: 10099: 10095: 10091: 10086: 10079: 10075: 10074:Faulkner 1952 10070: 10063: 10061:0-486-60288-5 10057: 10053: 10048: 10047: 10038: 10030: 10024: 10017: 10013: 10009: 10005: 10001: 9995: 9988: 9983: 9974: 9969: 9965: 9961: 9954: 9947: 9942: 9935: 9930: 9923: 9918: 9911: 9906: 9900: 9896: 9895:Faulkner 1952 9891: 9884: 9879: 9872: 9867: 9860: 9856: 9855:Faulkner 1952 9851: 9844: 9839: 9832: 9828: 9823: 9816: 9815:Merserve 1983 9811: 9804: 9799: 9792: 9787: 9781:, p. 320 9780: 9775: 9769: 9765: 9764:Faulkner 1952 9760: 9753: 9752:Faulkner 1952 9748: 9741: 9736: 9729: 9724: 9717: 9712: 9705: 9700: 9698: 9690: 9685: 9678: 9673: 9654: 9647: 9641: 9633: 9627: 9623: 9619: 9615: 9609: 9601: 9595: 9591: 9584: 9576: 9570: 9566: 9559: 9552: 9548: 9544: 9540: 9536: 9532: 9527: 9520: 9516: 9512: 9508: 9504: 9500: 9495: 9487: 9485:0-292-78149-0 9481: 9477: 9473: 9472: 9464: 9458:, p. 36. 9457: 9452: 9446:, p. 30. 9445: 9440: 9433: 9429: 9428: 9421: 9414: 9409: 9402: 9399:Heath, T.L., 9396: 9390:, p. 117 9389: 9384: 9377: 9372: 9365: 9360: 9353: 9348: 9341: 9336: 9328: 9324: 9317: 9310: 9303: 9299: 9294: 9287: 9282: 9275: 9274: 9267: 9260: 9259: 9252: 9245: 9241: 9240: 9233: 9231: 9229: 9221: 9215: 9209:, p. 153 9208: 9203: 9197:, p. 326 9196: 9191: 9189: 9182: 9177: 9175:0-471-75715-2 9171: 9167: 9166: 9158: 9151: 9146: 9140:, p. 316 9139: 9134: 9128:, p. 130 9127: 9122: 9115: 9110: 9103: 9098: 9091: 9086: 9079: 9074: 9067: 9063: 9058: 9052:, p. 434 9051: 9046: 9039: 9035: 9031: 9027: 9021: 9014: 9009: 9003:, p. 319 9002: 8997: 8993: 8977: 8968: 8959: 8952: 8948: 8945:According to 8942: 8933: 8929: 8919: 8916: 8914: 8911: 8909: 8906: 8904: 8901: 8899: 8896: 8894: 8891: 8889: 8886: 8884: 8881: 8880: 8871: 8866: 8859: 8855: 8851: 8847: 8843: 8839: 8837: 8834: 8819: 8816: 8813: 8810: 8806: 8797: 8794: 8769: 8766: 8763: 8760: 8756: 8747: 8744: 8720: 8717: 8714: 8711: 8707: 8698: 8695: 8687: 8684: 8676: 8672: 8669: 8658: 8655: 8644: 8642: 8639: 8638: 8637: 8635: 8628: 8627:wave equation 8624: 8623:heat equation 8620: 8615: 8611: 8608: 8605: 8602: 8598: 8594: 8590: 8572: 8568: 8564: 8559: 8555: 8532: 8528: 8508: 8503: 8499: 8495: 8490: 8486: 8477: 8473: 8469: 8465: 8461: 8457: 8454: 8451: 8447: 8443: 8439: 8420: 8416: 8412: 8407: 8403: 8395: 8378: 8374: 8366: 8349: 8345: 8341: 8336: 8332: 8324: 8323: 8309: 8306: 8303: 8300: 8297: 8294: 8291: 8288: 8280: 8276: 8272: 8256: 8251: 8246: 8243: 8240: 8236: 8232: 8229: 8226: 8221: 8216: 8213: 8210: 8206: 8202: 8197: 8192: 8188: 8184: 8181: 8178: 8173: 8168: 8164: 8160: 8155: 8150: 8146: 8137: 8136:diagonal form 8133: 8129: 8125: 8123: 8120: 8119: 8118: 8115: 8113: 8102: 8100: 8096: 8095:elliptic cone 8091: 8089: 8084: 8082: 8077: 8075: 8071: 8067: 8054: 8038: 8034: 8025: 8008: 8004: 7995: 7980: 7960: 7940: 7937: 7929: 7925: 7921: 7918: 7913: 7909: 7905: 7876: 7873: 7870: 7859: 7845: 7840: 7836: 7832: 7829: 7824: 7820: 7816: 7794: 7790: 7767: 7763: 7754: 7753: 7752: 7749: 7747: 7743: 7732: 7730: 7726: 7722: 7718: 7714: 7708: 7698: 7694: 7687: 7680: 7673: 7666: 7660: 7656: 7652: 7636: 7632: 7628: 7620: 7606: 7598: 7594: 7588: 7582: 7580: 7574: 7572: 7568: 7562: 7560: 7556: 7552: 7536: 7533: 7530: 7527: 7522: 7518: 7514: 7509: 7505: 7496: 7480: 7477: 7474: 7471: 7468: 7463: 7459: 7450: 7446: 7441: 7439: 7438:straight line 7435: 7431: 7426: 7423: 7417: 7407: 7405: 7403: 7399: 7393: 7385: 7380: 7379:cyclic points 7376: 7372: 7368: 7364: 7360: 7359:straight line 7355: 7353: 7349: 7345: 7340: 7336: 7331: 7325: 7323: 7318: 7314: 7309: 7306: 7290: 7287: 7282: 7278: 7274: 7269: 7265: 7244: 7241: 7238: 7235: 7232: 7212: 7209: 7204: 7200: 7196: 7191: 7187: 7177: 7166: 7163: 7148: 7144: 7129: 7125: 7115: 7111: 7100: 7091: 7073: 7064: 7057: 7039: 7030: 7023: 7015: 7004: 6996: 6985: 6977: 6965: 6957: 6953: 6946: 6942: 6938: 6934: 6930: 6926: 6922: 6918: 6912: 6901: 6893: 6881: 6873: 6858: 6854: 6842: 6834: 6822: 6814: 6802: 6794: 6782: 6774: 6762: 6751: 6747: 6743: 6739: 6735: 6730: 6725: 6720:Constructions 6717: 6715: 6714:Steiner conic 6710: 6708: 6704: 6699: 6694: 6693: 6687: 6681: 6676: 6675: 6669: 6664: 6659: 6655: 6651: 6645: 6641: 6637: 6631: 6625: 6620: 6615: 6610: 6607: 6602: 6593: 6588: 6586: 6582: 6578: 6573: 6563: 6561: 6555: 6553: 6549: 6545: 6541: 6531: 6517: 6514: 6511: 6503: 6502:pappian plane 6498: 6496: 6491: 6477: 6469: 6453: 6445: 6426: 6420: 6397: 6391: 6371: 6363: 6340: 6334: 6311: 6305: 6285: 6277: 6273: 6270:resp.) and a 6257: 6237: 6217: 6214: 6211: 6188: 6182: 6179: 6173: 6167: 6159: 6158: 6157: 6155: 6154:Jakob Steiner 6151: 6142: 6137: 6136:Steiner conic 6127: 6122: 6115: 6113: 6109: 6105: 6100: 6086: 6083:which is the 6074: 6062: 6058: 6057:absolute line 6053: 6051: 6046: 6037: 6024: 6019: 6005: 5999: 5995: 5991: 5987: 5983: 5979: 5972: 5970: 5965: 5948: 5944: 5937: 5932: 5927: 5920: 5915: 5910: 5903: 5898: 5893: 5886: 5882: 5879: 5872: 5871: 5870: 5853: 5850: 5847: 5842: 5838: 5834: 5831: 5828: 5825: 5822: 5819: 5816: 5813: 5810: 5807: 5804: 5801: 5796: 5792: 5788: 5785: 5782: 5779: 5776: 5773: 5770: 5765: 5761: 5757: 5750: 5749: 5748: 5745: 5743: 5724: 5721: 5717: 5710: 5703: 5696: 5689: 5684: 5677: 5672: 5668: 5664: 5659: 5655: 5651: 5644: 5640: 5636: 5631: 5626: 5622: 5618: 5611: 5607: 5603: 5598: 5594: 5590: 5585: 5578: 5573: 5566: 5561: 5556: 5549: 5541: 5540: 5539: 5537: 5518: 5515: 5510: 5506: 5502: 5499: 5496: 5493: 5490: 5487: 5484: 5481: 5478: 5475: 5470: 5466: 5462: 5459: 5456: 5453: 5450: 5447: 5442: 5438: 5434: 5427: 5426: 5425: 5423: 5413: 5411: 5405: 5402: 5392: 5390: 5386: 5381: 5375: 5373: 5369: 5365: 5361: 5350: 5348: 5344: 5338: 5336: 5332: 5328: 5324: 5320: 5313: 5309: 5305: 5301: 5291: 5288: 5283: 5278: 5273: 5268: 5264: 5260: 5259:Pierre Fermat 5256: 5252: 5250: 5246: 5242: 5241:Blaise Pascal 5238: 5234: 5232: 5228: 5221: 5220: 5214: 5205: 5203: 5198: 5196: 5192: 5187: 5185: 5181: 5177: 5170:Islamic world 5167: 5165: 5154: 5150: 5147: 5146: 5142: 5130: 5122: 5117: 5108: 5106: 5102: 5091: 5087: 5083: 5081: 5077: 5073: 5058: 5056: 5052: 5048: 5043: 5041: 5036: 5032: 5029: 5024: 5022: 5018: 5014: 5013:tangent lines 5009: 5007: 5003: 4999: 4994: 4990: 4988: 4984: 4980: 4976: 4966: 4964: 4959: 4958:a hyperbola. 4955: 4948: 4941: 4933: 4927: 4924: 4918: 4898: 4892: 4889: 4886: 4883: 4880: 4877: 4873: 4868: 4865: 4858: 4857: 4856: 4853: 4848: 4840: 4835: 4826: 4810: 4806: 4800: 4796: 4792: 4781: 4765: 4742: 4739: 4731: 4723: 4719: 4715: 4709: 4706: 4703: 4697: 4694: 4688: 4685: 4682: 4676: 4671: 4667: 4659: 4658: 4657: 4642: 4635: 4630: 4626: 4622: 4615: 4611: 4607: 4602: 4595: 4586: 4568: 4564: 4541: 4537: 4513: 4510: 4507: 4493: 4489: 4481: 4477: 4474: 4468: 4458: 4449: 4435: 4431: 4423: 4419: 4416: 4410: 4400: 4387: 4386: 4385: 4368: 4365: 4362: 4351: 4346: 4342: 4336: 4332: 4324: 4320: 4317: 4311: 4301: 4292: 4281: 4277: 4271: 4266: 4262: 4254: 4250: 4247: 4241: 4231: 4218: 4217: 4216: 4196: 4190: 4181: 4154: 4151: 4148: 4145: 4142: 4139: 4136: 4133: 4130: 4127: 4122: 4118: 4114: 4111: 4108: 4105: 4102: 4099: 4094: 4090: 4086: 4079: 4078: 4077: 4073: 4063: 4049: 4044: 4039: 4035: 4029: 4026: 4023: 4020: 3994: 3991: 3988: 3979: 3976: 3971: 3963: 3960: 3957: 3948: 3943: 3939: 3929: 3926: 3921: 3913: 3910: 3907: 3898: 3893: 3889: 3878: 3877: 3876: 3873: 3867: 3844: 3833: 3829: 3825: 3820: 3812: 3809: 3806: 3798: 3792: 3789: 3786: 3780: 3771: 3767: 3763: 3758: 3750: 3747: 3744: 3736: 3729: 3726: 3719: 3718: 3717: 3713: 3709: 3687: 3684: 3681: 3678: 3675: 3672: 3669: 3666: 3663: 3660: 3657: 3652: 3648: 3644: 3641: 3638: 3635: 3632: 3629: 3624: 3620: 3616: 3609: 3608: 3607: 3599: 3596: 3592: 3586: 3581: 3577: 3572: 3568: 3561: 3557: 3553: 3548: 3544: 3533: 3509: 3503: 3499: 3494: 3493: 3491: 3485: 3481: 3476: 3473: 3467: 3463: 3458: 3453: 3447: 3441: 3437: 3432: 3431: 3429: 3423: 3419: 3414: 3413: 3412: 3410: 3405: 3392: 3388: 3381: 3376: 3372: 3368: 3361: 3357: 3353: 3348: 3341: 3333: 3321: 3318:, called the 3305: 3302: 3299: 3296: 3291: 3287: 3272: 3270: 3265: 3252: 3249: 3244: 3238: 3231: 3224: 3218: 3211: 3205: 3200: 3196: 3192: 3187: 3183: 3179: 3172: 3168: 3164: 3159: 3154: 3150: 3146: 3139: 3135: 3131: 3126: 3122: 3118: 3113: 3107: 3100: 3094: 3089: 3084: 3078: 3067: 3054: 3051: 3048: 3045: 3040: 3034: 3027: 3021: 3014: 3008: 3003: 2997: 2992: 2987: 2981: 2974: 2968: 2961: 2955: 2950: 2946: 2942: 2935: 2931: 2927: 2922: 2916: 2909: 2903: 2898: 2892: 2880: 2870: 2864: 2845: 2842: 2839: 2836: 2833: 2830: 2827: 2824: 2821: 2818: 2815: 2810: 2806: 2802: 2799: 2796: 2793: 2790: 2787: 2782: 2778: 2774: 2767: 2766: 2765: 2763: 2759: 2755: 2751: 2725: 2719: 2715: 2710: 2707: 2699: 2695: 2689: 2686: 2681: 2678: 2675: 2671: 2663: 2662: 2660: 2657: 2637: 2634: 2631: 2628: 2625: 2622: 2619: 2616: 2613: 2610: 2599: 2593: 2590: 2587: 2584: 2581: 2578: 2575: 2572: 2569: 2559: 2558: 2556: 2553: 2537: 2531: 2528: 2525: 2522: 2517: 2513: 2509: 2499: 2498: 2496: 2493: 2477: 2471: 2468: 2465: 2462: 2459: 2456: 2453: 2450: 2447: 2437: 2436: 2434: 2431: 2415: 2409: 2406: 2403: 2400: 2397: 2394: 2391: 2388: 2385: 2375: 2374: 2372: 2369: 2368: 2367: 2365: 2360: 2357: 2353: 2347: 2343: 2337: 2331: 2325: 2303: 2298: 2294: 2290: 2287: 2284: 2277: 2276: 2274: 2258: 2255: 2252: 2245: 2241: 2235: 2231: 2225: 2218: 2214: 2208: 2204: 2194: 2193: 2191: 2175: 2172: 2169: 2166: 2158: 2155: 2152: 2149: 2146: 2141: 2137: 2129: 2128: 2126: 2110: 2107: 2104: 2097: 2093: 2087: 2083: 2077: 2070: 2066: 2060: 2056: 2046: 2045: 2043: 2027: 2022: 2018: 2014: 2009: 2005: 2001: 1996: 1992: 1984: 1983: 1981: 1980: 1979: 1975: 1971: 1963: 1959: 1952: 1948: 1943: 1939: 1934: 1931: 1927: 1920: 1909: 1905: 1901: 1897: 1896: 1890: 1886: 1879: 1873: 1869: 1865: 1859: 1855: 1851: 1840: 1835:and the foci 1832: 1822: 1818: 1814: 1810: 1801: 1793: 1785: 1755: 1751: 1747: 1742: 1738: 1731: 1727: 1717: 1701: 1696: 1692: 1682: 1664: 1660: 1656: 1651: 1647: 1637: 1617: 1613: 1607: 1603: 1597: 1594: 1585: 1571: 1568: 1561: 1557: 1551: 1547: 1541: 1534: 1530: 1524: 1520: 1510: 1508: 1505: 1504: 1488: 1485: 1478: 1463: 1460: 1453: 1450: 1435: 1428: 1413: 1410: 1407: 1404: 1399: 1395: 1387: 1385: 1382: 1381: 1361: 1357: 1353: 1348: 1344: 1337: 1333: 1323: 1307: 1302: 1298: 1288: 1270: 1266: 1262: 1257: 1253: 1243: 1223: 1219: 1213: 1209: 1203: 1200: 1191: 1177: 1174: 1167: 1163: 1157: 1153: 1147: 1140: 1136: 1130: 1126: 1116: 1114: 1111: 1110: 1088: 1073: 1066: 1051: 1044: 1029: 1022: 1005: 1001: 997: 992: 988: 984: 979: 975: 967: 965: 962: 961: 956: 951: 947: 942: 938: 933: 929: 924: 921: 918: 917: 914: 900: 897: 894: 891: 888: 863: 860: 855: 852: 849: 846: 836: 822: 819: 816: 813: 803: 789: 786: 783: 780: 770: 769: 768: 765: 751: 747: 742: 734: 726: 712: 711: 706: 701: 695: 690: 684: 680: 676: 671: 665: 660: 658: 654: 649: 638: 629: 626: 618: 612: 605: 598: 596: 592: 587: 574: 568: 565: 562: 557: 554: 551: 528: 525: 505: 496: 493: 489: 488:a hyperbola. 485: 478: 471: 465: 453: 452: 443: 442: 429: 417: 416:infinitesimal 407: 400: 393: 388: 383: 374: 372: 368: 365:Compare also 363: 361: 357: 353: 349: 345: 341: 337: 333: 329: 324: 322: 320: 315: 311: 307: 306:cutting plane 304:, called the 303: 293: 291: 283: 276: 269: 262: 254: 245: 243: 239: 235: 230: 216: 213: 210: 207: 204: 201: 198: 195: 192: 189: 184: 180: 176: 173: 170: 167: 164: 161: 156: 152: 148: 140: 136: 132: 128: 127: 122: 118: 117: 112: 108: 103: 101: 97: 93: 89: 85: 81: 77: 73: 69: 65: 61: 57: 56:conic section 48: 40: 32: 19: 11053:Prym variety 11027:Stable curve 11017:Hodge bundle 11007:ELSV formula 10809:Fermat curve 10793: 10766:Plane curves 10729:Higher genus 10704:Applications 10629:Modular form 10504: 10481: 10463: 10439: 10418:. Springer. 10415: 10395: 10376: 10356: 10333: 10313: 10298:20 September 10296:, retrieved 10288: 10278: 10269: 10266:Eves, Howard 10247: 10237: 10218: 10195: 10175: 10153: 10127: 10120:Bibliography 10105: 10093: 10085: 10069: 10045: 10037: 10023: 10003: 9994: 9982: 9963: 9959: 9953: 9948:, p. 70 9941: 9936:, p. 19 9929: 9924:, p. 14 9917: 9905: 9890: 9885:, p. 80 9883:Coxeter 1964 9878: 9873:, p. 60 9871:Coxeter 1964 9866: 9850: 9838: 9826: 9822: 9810: 9798: 9793:, p. 80 9791:Coxeter 1993 9786: 9774: 9759: 9754:, p. 71 9747: 9735: 9723: 9718:, p. 27 9711: 9684: 9672: 9660:. Retrieved 9653:the original 9640: 9617: 9608: 9589: 9583: 9564: 9558: 9534: 9526: 9506: 9499:Boyer, C. B. 9494: 9470: 9463: 9451: 9439: 9430:, edited by 9426: 9420: 9415:, p. 28 9408: 9400: 9395: 9383: 9378:, p. 18 9371: 9359: 9347: 9342:, p. 28 9335: 9326: 9322: 9309: 9301: 9293: 9288:, p. 17 9281: 9271: 9266: 9256: 9251: 9238: 9219: 9214: 9202: 9164: 9157: 9152:, p. 30 9145: 9133: 9121: 9109: 9097: 9085: 9073: 9057: 9045: 9025: 9020: 9015:, p. 13 9008: 8996: 8976: 8967: 8958: 8941: 8932: 8667: 8653: 8632: 8614:second order 8449: 8445: 8441: 8278: 8274: 8270: 8131: 8116: 8112:discriminant 8108: 8092: 8085: 8078: 8063: 7750: 7738: 7724: 7720: 7710: 7692: 7685: 7678: 7671: 7664: 7658: 7654: 7650: 7634: 7630: 7626: 7618: 7604: 7596: 7592: 7586: 7583: 7575: 7570: 7563: 7559:multiplicity 7554: 7494: 7442: 7427: 7421: 7419: 7406: 7391: 7383: 7363:tangent line 7356: 7351: 7339:intersection 7335:multiplicity 7329: 7326: 7316: 7310: 7175: 7172: 7164: 7146: 7142: 7127: 7123: 7113: 7109: 7098: 7089: 7078:starting at 7071: 7062: 7055: 7044:starting at 7037: 7028: 7021: 7013: 7002: 6994: 6983: 6975: 6963: 6955: 6951: 6944: 6940: 6936: 6932: 6928: 6924: 6920: 6916: 6910: 6899: 6891: 6879: 6871: 6863: 6840: 6832: 6820: 6812: 6800: 6792: 6780: 6772: 6760: 6749: 6745: 6741: 6737: 6733: 6728: 6726: 6723: 6711: 6706: 6702: 6697: 6691: 6685: 6679: 6673: 6667: 6661:. Following 6657: 6653: 6649: 6643: 6639: 6635: 6629: 6627:with a line 6623: 6613: 6600: 6591: 6589: 6584: 6580: 6575: 6559: 6556: 6551: 6547: 6543: 6537: 6499: 6494: 6492: 6467: 6384:of a pencil 6361: 6359: 6147: 6120: 6116: 6103: 6101: 6072: 6060: 6056: 6054: 6043: 5997: 5993: 5989: 5985: 5981: 5977: 5973: 5966: 5963: 5868: 5746: 5741: 5739: 5533: 5419: 5410:double point 5406: 5398: 5379: 5376: 5356: 5339: 5316: 5294:Applications 5253: 5235: 5225: 5217: 5199: 5188: 5180:Omar Khayyám 5173: 5151: 5144: 5140: 5126: 5120: 5104: 5100: 5084: 5069: 5051:laminar flow 5044: 5033: 5027: 5025: 5020: 5016: 5010: 5005: 5001: 4997: 4995: 4991: 4972: 4960: 4953: 4946: 4939: 4931: 4928: 4922: 4916: 4913: 4851: 4844: 4838: 4757: 4528: 4383: 4170: 4075: 4010:where again 4009: 3874: 3859: 3711: 3707: 3703: 3605: 3594: 3590: 3588:and the sum 3584: 3570: 3566: 3559: 3555: 3546: 3542: 3539: 3515: 3501: 3497: 3483: 3479: 3465: 3461: 3445: 3439: 3435: 3421: 3417: 3406: 3320:discriminant 3278: 3275:Discriminant 3266: 3068: 2882: 2863:real numbers 2860: 2747: 2361: 2355: 2351: 2345: 2341: 2335: 2329: 2323: 2320: 1973: 1969: 1961: 1957: 1950: 1946: 1941: 1937: 1935: 1929: 1925: 1918: 1907: 1903: 1899: 1893: 1888: 1884: 1877: 1871: 1867: 1863: 1857: 1853: 1849: 1838: 1830: 1820: 1806: 954: 945: 936: 927: 880: 766: 749: 745: 743: 732: 724: 708: 704: 702: 693: 691: 682: 675:latus rectum 674: 672: 663: 661: 656: 652: 650: 643: 624: 616: 610: 603: 599: 588: 497: 494: 490: 483: 476: 469: 463: 462:(called the 451:eccentricity 449: 448:(called the 439: 438:(called the 425: 405: 398: 391: 387:eccentricity 364: 359: 355: 351: 344:closed curve 325: 318: 313: 305: 299: 287: 231: 126:eccentricity 124: 120: 114: 104: 63: 59: 55: 53: 10928:Polar curve 10008:Mineola, NY 10000:Korn, T. M. 9989:, p. 6 9912:, p. 5 9897:, pp.  9857:, pp.  9432:T. L. Heath 9236:Spain, B., 9066:Kendig 2005 9024:Cohen, D., 8547:(or 0), or 8446:degenerate, 7725:base points 7713:five points 6548:point conic 6534:Line conics 6362:perspective 6276:perspective 5277:Jan de Witt 5267:John Wallis 5219:Cyclopaedia 4585:eigenvalues 3552:determinant 2192:Hyperbola: 1942:equilateral 1938:rectangular 11143:Categories 10923:Dual curve 10551:Topics in 10090:Berger, M. 9934:Downs 2003 9922:Downs 2003 9910:Downs 2003 9766:, p.  9740:Artzy 2008 9728:Artzy 2008 9704:Boyer 2004 9689:Boyer 2004 9543:Heidelberg 9456:Boyer 2004 9376:Boyer 2004 9364:Boyer 2004 9352:Downs 2003 9329:: 295–348. 8988:References 8951:Boyer 2004 8675:classified 8612:(PDEs) of 8450:indefinite 7648:; and let 7551:degeneracy 7422:degenerate 7348:osculating 6765:, a point 6606:involutory 6552:line conic 6495:projective 6272:projective 5969:degenerate 5191:Abu al-Jud 5160: 350 5136: 190 5097: 212 5090:Archimedes 5080:generatrix 5072:Menaechmus 5055:turbulence 4969:Properties 4070:See also: 3536:Invariants 2762:degenerate 2327:-axis and 2127:Parabola: 746:minor axis 705:major axis 319:degenerate 296:Definition 86:, and the 11036:Morphisms 10784:Bitangent 10506:MathWorld 10380:, Dover, 10251:, Dover, 10179:, Dover, 10173:(2004) , 10156:, Dover, 10152:(2008) , 10014:, 1961), 9779:Eves 1963 9677:Katz 1998 9549:, 1983), 9517:, 1968), 9444:Eves 1963 9413:Eves 1963 9388:Katz 1998 9036:, 2006), 9001:Eves 1963 8798:⁡ 8748:⁡ 8699:⁡ 8688:≤ 8636:include: 8565:− 8470:, zero – 8455:Curvature 8442:definite, 8413:− 8295:ℓ 8247:ℓ 8233:− 8230:⋯ 8227:− 8203:− 8182:⋯ 7981:μ 7961:λ 7922:μ 7906:λ 7877:μ 7871:λ 7833:μ 7817:λ 7717:collinear 7493:or to an 7445:empty set 7367:hyperbola 7275:− 6609:bijection 6478:π 6444:bijection 6372:π 6286:π 6156:in 1867. 6150:synthetic 6112:collinear 5538:notation 5319:astronomy 5312:Hyperbola 5287:kinematic 5164:directrix 4983:collinear 4893:θ 4890:⁡ 4841:increases 4807:λ 4797:λ 4790:Δ 4710:− 4695:λ 4677:− 4668:λ 4565:λ 4538:λ 4499:Δ 4490:λ 4475:− 4462:~ 4441:Δ 4432:λ 4417:− 4404:~ 4343:λ 4333:λ 4318:− 4305:~ 4278:λ 4263:λ 4248:− 4235:~ 4200:~ 4185:~ 4030:− 4018:Δ 3983:Δ 3977:− 3949:− 3933:Δ 3927:− 3886:Δ 3810:− 3781:η 3748:− 3490:hyperbola 3297:− 2638:ψ 2635:⁡ 2623:ψ 2620:⁡ 2611:± 2594:θ 2591:⁡ 2579:θ 2576:⁡ 2555:Hyperbola 2472:θ 2469:⁡ 2457:θ 2454:⁡ 2410:θ 2407:⁡ 2395:θ 2392:⁡ 2226:− 2044:Ellipse: 1843:. Define 1542:− 1507:hyperbola 1354:− 1263:− 1204:− 1096:∞ 922:equation 781:ℓ 569:β 566:⁡ 558:α 555:⁡ 526:α 506:β 464:directrix 356:hyperbola 336:hyperbola 282:Hyperbola 121:directrix 80:hyperbola 10436:(1988), 10408:76087042 10310:(1998), 10268:(1963), 10216:(1964), 10196:Geometry 9843:Hartmann 9803:Hartmann 9742:, p. 159 9616:(2010). 9501:, & 9244:Pergamon 9030:Stamford 8947:Plutarch 8877:See also 7567:cylinder 7375:parabola 6809:and let 6663:Gergonne 6592:polarity 6581:polarity 6544:envelope 6364:mapping 6278:mapping 6274:but not 6073:midpoint 6045:Metrical 5308:Parabola 4963:dynamics 4583:are the 3472:parabola 3411:, then: 2495:Parabola 1982:Circle: 1813:rotation 1384:parabola 614:. (Here 352:parabola 348:parallel 332:parabola 275:Parabola 84:parabola 11096:Tacnode 11081:Crunode 9845:, p. 19 9817:, p. 65 9805:, p. 38 9662:10 June 9511:Hoboken 8464:surface 7645:⁠ 7623:⁠ 7615:⁠ 7601:⁠ 7371:ellipse 7344:tangent 7007:⁠ 6991:⁠ 6904:⁠ 6888:⁠ 6884:⁠ 6868:⁠ 6829:. Then 6538:By the 5372:quadric 5304:Ellipse 5202:Al-Kuhi 5195:quartic 5061:History 4938:0 < 3428:ellipse 3330:is the 2867:A, B, C 2748:In the 2433:Ellipse 1936:For a 1892:, with 1113:ellipse 737:, with 677:is the 468:0 < 466:). For 328:ellipse 278:  268:Ellipse 242:complex 88:ellipse 11076:Acnode 11000:Moduli 10470:  10452:  10422:  10406:  10384:  10364:  10344:  10334:Conics 10322:  10255:  10226:  10203:  10183:  10160:  10138:  10098:p. 127 10076:, pg. 10058:  9628:  9596:  9571:  9539:Berlin 9519:p. 219 9482:  9172:  9038:p. 844 8673:) are 7695:> 0 7681:< 0 7669:. If 7555:double 7398:circle 6923:, 0), 6837:meets 6757:, say 6604:is an 6104:circle 6071:, the 5536:matrix 5534:Or in 5323:orbits 5321:: the 5310:, and 5300:Circle 5222:, 1728 5208:Europe 5155:(died 5145:Conics 5131:(died 5121:Conics 5092:(died 5086:Euclid 5047:smooth 4956:> 1 4942:< 1 4914:where 4782:, and 4758:— and 4529:where 3870:η = −1 3860:where 3486:> 0 3452:circle 3424:< 0 3326:where 2752:, the 2371:Circle 1895:radius 964:circle 844:  811:  778:  657:center 486:> 1 472:< 1 340:circle 338:. The 334:, and 321:conics 314:nappes 261:Circle 92:circle 90:; the 82:, the 10293:(PDF) 10016:p. 42 9899:52–53 9859:48–49 9656:(PDF) 9649:(PDF) 9551:p. 73 9319:(PDF) 8924:Notes 8462:of a 8138:, as 8074:above 7434:point 7390:(1, – 6968:into 6949:and 6817:meet 6797:meet 6777:meet 6701:. An 6674:polar 6442:is a 6327:onto 6250:and 5399:In a 3862:η = 1 3576:trace 3574:(the 3269:below 2756:of a 2754:graph 679:chord 441:focus 428:locus 394:= 1/2 302:plane 116:focus 76:plane 68:curve 66:is a 62:or a 60:conic 11086:Cusp 10468:ISBN 10450:ISBN 10420:ISBN 10404:LCCN 10382:ISBN 10362:ISBN 10342:ISBN 10320:ISBN 10300:2014 10253:ISBN 10224:ISBN 10201:ISBN 10181:ISBN 10158:ISBN 10136:ISBN 10056:ISBN 9664:2011 9626:ISBN 9594:ISBN 9569:ISBN 9480:ISBN 9170:ISBN 8814:> 8715:< 8458:The 8081:oval 7973:and 7782:and 7430:apex 7394:, 0) 7388:and 7386:, 0) 7382:(1, 7158:and 7150:and 7126:(0, 7121:and 7108:1 ≤ 7106:for 6958:, 0) 6911:ABCD 6707:line 6705:(or 6692:pole 6689:the 6683:and 6656:) = 6647:and 6642:) = 6468:axis 6095:and 6067:and 5257:and 5239:and 5008:≤5. 4556:and 3528:and 3520:and 3443:and 3324:− 4Δ 2865:and 2632:sinh 2617:cosh 2366:as, 2349:and 2170:> 1966:and 1921:, 0) 1841:, 0) 1833:, 0) 1815:and 1451:N/A 898:> 744:The 735:, 0) 729:and 727:, 0) 703:The 692:The 673:The 662:The 651:The 360:both 310:cone 238:real 9968:doi 8868:In 8782:or 8648:PSL 8281:so 7900:det 7688:= 0 7674:= 0 7667:≠ 0 7657:− 4 7627:BED 7595:= ( 7069:to 7035:to 6943:, 2 6935:), 6931:, 2 6906:= 1 6825:at 6805:in 6785:in 6695:of 6677:of 6633:by 6298:of 6123:= 0 5420:In 5279:'s 5143:or 4949:= 1 4934:= 0 4887:cos 4845:In 4215:as 3545:– 4 3504:= 0 3495:if 3482:− 4 3477:if 3468:= 0 3464:− 4 3459:if 3448:= 0 3433:if 3420:− 4 3415:if 3271:). 2588:tan 2573:sec 2466:sin 2451:cos 2404:sin 2389:cos 2354:= − 1972:, − 1940:or 1928:= − 1882:so 1880:= 0 689:). 563:cos 552:cos 479:= 1 408:= 2 401:= 1 280:4: 273:3: 266:2: 259:1: 111:set 11145:: 10503:. 10444:, 10402:, 10340:, 10336:, 10134:. 10130:. 10092:, 10078:64 10054:, 10052:63 10010:: 10002:, 9964:22 9962:, 9768:72 9696:^ 9624:. 9622:30 9545:: 9533:, 9513:: 9505:, 9474:. 9327:14 9325:. 9321:. 9300:. 9227:^ 9187:^ 9179:, 9032:: 8795:tr 8745:tr 8696:tr 8662:SL 8279:m, 8271:k, 8090:. 7731:. 7697:. 7672:β 7659:AC 7653:= 7635:AE 7633:− 7631:CD 7629:− 7621:+ 7599:− 7597:AC 7593:β 7537:0. 7404:. 7354:. 7330:CP 7324:. 7317:CP 7145:, 7112:≤ 7099:DD 7096:∩ 7090:AA 7056:AB 7022:BC 7014:BC 6984:AB 6976:AC 6964:BC 6954:(− 6939:(− 6886:+ 6841:EG 6833:AN 6821:LM 6813:CD 6801:EG 6793:BC 6789:, 6781:DE 6773:AB 6761:EG 6748:, 6744:, 6740:, 6736:, 6716:. 6665:, 6594:, 6590:A 6493:A 6490:. 6360:A 6148:A 6114:. 6099:. 6089:AB 6077:AB 5996:, 5992:, 5988:, 5984:, 5980:, 5971:. 5744:. 5725:0. 5519:0. 5337:. 5306:, 5302:, 5204:. 5157:c. 5133:c. 5107:. 5094:c. 5057:. 5042:. 4989:. 3710:= 3708:AC 3593:+ 3569:+ 3562:/4 3558:– 3556:AC 3547:AC 3532:. 3500:+ 3492:; 3484:AC 3466:AC 3438:= 3430:; 3422:AC 3253:0. 3055:0. 2661:: 2557:: 2497:: 2435:: 2373:: 2359:. 2344:= 1978:. 1968:(− 1960:, 1949:= 1906:= 1902:= 1887:= 1870:+ 1866:= 1856:− 1852:= 1837:(± 1829:(± 958:) 949:) 940:) 931:) 913:. 723:(− 597:. 330:, 292:. 217:0. 58:, 54:A 10544:e 10537:t 10530:v 10517:. 10509:. 10428:. 10144:. 10100:. 10080:. 10031:. 10018:. 10006:( 9977:. 9970:: 9861:. 9666:. 9634:. 9602:. 9577:. 9553:. 9541:/ 9537:( 9521:. 9509:( 9488:. 9246:. 9040:. 9028:( 8860:. 8820:, 8817:1 8811:2 8807:/ 8802:| 8791:| 8770:, 8767:1 8764:= 8761:2 8757:/ 8752:| 8741:| 8721:, 8718:1 8712:2 8708:/ 8703:| 8692:| 8685:0 8670:) 8668:R 8666:( 8664:2 8656:) 8654:R 8652:( 8650:2 8603:. 8573:2 8569:y 8560:2 8556:x 8533:2 8529:x 8509:, 8504:2 8500:y 8496:+ 8491:2 8487:x 8421:2 8417:y 8408:2 8404:x 8379:2 8375:x 8350:2 8346:y 8342:+ 8337:2 8333:x 8310:. 8307:n 8304:= 8301:m 8298:+ 8292:+ 8289:k 8275:ℓ 8257:, 8252:2 8244:+ 8241:k 8237:x 8222:2 8217:1 8214:+ 8211:k 8207:x 8198:2 8193:k 8189:x 8185:+ 8179:+ 8174:2 8169:2 8165:x 8161:+ 8156:2 8151:1 8147:x 8132:n 8039:0 8035:C 8009:0 8005:C 7941:0 7938:= 7935:) 7930:2 7926:C 7919:+ 7914:1 7910:C 7903:( 7880:) 7874:, 7868:( 7846:. 7841:2 7837:C 7830:+ 7825:1 7821:C 7795:2 7791:C 7768:1 7764:C 7693:α 7686:α 7679:α 7665:β 7655:B 7651:α 7642:4 7639:/ 7619:F 7617:) 7612:4 7609:/ 7605:B 7587:β 7534:= 7531:1 7528:+ 7523:2 7519:y 7515:+ 7510:2 7506:x 7481:, 7478:0 7475:= 7472:1 7469:+ 7464:2 7460:x 7392:i 7384:i 7291:1 7288:= 7283:2 7279:w 7270:2 7266:x 7245:, 7242:w 7239:i 7236:= 7233:y 7213:1 7210:= 7205:2 7201:y 7197:+ 7192:2 7188:x 7176:C 7160:D 7156:A 7152:P 7147:D 7143:A 7138:D 7134:A 7130:) 7128:b 7124:P 7119:A 7114:n 7110:i 7103:i 7094:i 7084:B 7080:A 7075:n 7072:D 7066:1 7063:D 7050:C 7046:B 7041:n 7038:A 7032:1 7029:A 7003:a 6999:/ 6995:b 6970:n 6956:a 6952:D 6947:) 6945:b 6941:a 6937:C 6933:b 6929:a 6927:( 6925:B 6921:a 6919:( 6917:A 6900:b 6896:/ 6892:y 6880:a 6876:/ 6872:x 6851:E 6847:F 6827:N 6807:M 6787:L 6767:F 6755:E 6750:E 6746:D 6742:C 6738:B 6734:A 6698:q 6686:Q 6680:Q 6668:q 6658:Q 6654:q 6652:( 6650:π 6644:q 6640:Q 6638:( 6636:π 6630:q 6624:Q 6614:P 6601:P 6596:π 6518:V 6515:, 6512:U 6454:a 6430:) 6427:V 6424:( 6421:B 6401:) 6398:U 6395:( 6392:B 6344:) 6341:V 6338:( 6335:B 6315:) 6312:U 6309:( 6306:B 6258:V 6238:U 6218:V 6215:, 6212:U 6192:) 6189:V 6186:( 6183:B 6180:, 6177:) 6174:U 6171:( 6168:B 6121:e 6097:B 6093:A 6081:C 6069:B 6065:A 6025:. 6020:5 6015:P 6000:) 5998:F 5994:E 5990:D 5986:C 5982:B 5978:A 5976:( 5949:, 5945:) 5938:F 5933:E 5928:D 5921:E 5916:C 5911:B 5904:D 5899:B 5894:A 5887:( 5883:= 5880:M 5854:, 5851:0 5848:= 5843:2 5839:z 5835:F 5832:+ 5829:z 5826:y 5823:E 5820:2 5817:+ 5814:z 5811:x 5808:D 5805:2 5802:+ 5797:2 5793:y 5789:C 5786:+ 5783:y 5780:x 5777:B 5774:2 5771:+ 5766:2 5762:x 5758:A 5722:= 5718:) 5711:z 5704:y 5697:x 5690:( 5685:) 5678:F 5673:2 5669:/ 5665:E 5660:2 5656:/ 5652:D 5645:2 5641:/ 5637:E 5632:C 5627:2 5623:/ 5619:B 5612:2 5608:/ 5604:D 5599:2 5595:/ 5591:B 5586:A 5579:( 5574:) 5567:z 5562:y 5557:x 5550:( 5516:= 5511:2 5507:z 5503:F 5500:+ 5497:z 5494:y 5491:E 5488:+ 5485:z 5482:x 5479:D 5476:+ 5471:2 5467:y 5463:C 5460:+ 5457:y 5454:x 5451:B 5448:+ 5443:2 5439:x 5435:A 5380:R 5314:. 5006:k 5002:k 4998:k 4954:e 4947:e 4940:e 4932:e 4923:l 4917:e 4899:, 4884:e 4881:+ 4878:1 4874:l 4869:= 4866:r 4852:x 4839:e 4811:2 4801:1 4793:= 4766:S 4743:0 4740:= 4737:) 4732:2 4728:) 4724:2 4720:/ 4716:B 4713:( 4707:C 4704:A 4701:( 4698:+ 4692:) 4689:C 4686:+ 4683:A 4680:( 4672:2 4643:) 4636:C 4631:2 4627:/ 4623:B 4616:2 4612:/ 4608:B 4603:A 4596:( 4569:2 4542:1 4514:, 4511:1 4508:= 4502:) 4494:2 4486:( 4482:/ 4478:S 4469:2 4459:y 4450:+ 4444:) 4436:1 4428:( 4424:/ 4420:S 4411:2 4401:x 4369:, 4366:1 4363:= 4357:) 4352:2 4347:2 4337:1 4329:( 4325:/ 4321:S 4312:2 4302:y 4293:+ 4287:) 4282:2 4272:2 4267:1 4259:( 4255:/ 4251:S 4242:2 4232:x 4197:y 4191:, 4182:x 4155:0 4152:= 4149:F 4146:+ 4143:y 4140:E 4137:+ 4134:x 4131:D 4128:+ 4123:2 4119:y 4115:C 4112:+ 4109:y 4106:x 4103:B 4100:+ 4095:2 4091:x 4087:A 4050:. 4045:4 4040:2 4036:B 4027:C 4024:A 4021:= 3995:, 3992:0 3989:= 3986:] 3980:4 3972:2 3968:) 3964:C 3961:+ 3958:A 3955:( 3952:[ 3944:2 3940:e 3936:] 3930:4 3922:2 3918:) 3914:C 3911:+ 3908:A 3905:( 3902:[ 3899:+ 3894:4 3890:e 3845:, 3834:2 3830:B 3826:+ 3821:2 3817:) 3813:C 3807:A 3804:( 3799:+ 3796:) 3793:C 3790:+ 3787:A 3784:( 3772:2 3768:B 3764:+ 3759:2 3755:) 3751:C 3745:A 3742:( 3737:2 3730:= 3727:e 3712:B 3706:4 3688:, 3685:0 3682:= 3679:F 3676:+ 3673:y 3670:E 3667:+ 3664:x 3661:D 3658:+ 3653:2 3649:y 3645:C 3642:+ 3639:y 3636:x 3633:B 3630:+ 3625:2 3621:x 3617:A 3595:E 3591:D 3585:F 3571:C 3567:A 3560:B 3543:B 3530:B 3526:A 3522:B 3518:A 3510:. 3502:C 3498:A 3480:B 3474:; 3462:B 3446:B 3440:C 3436:A 3418:B 3393:. 3389:| 3382:C 3377:2 3373:/ 3369:B 3362:2 3358:/ 3354:B 3349:A 3342:| 3328:Δ 3306:C 3303:A 3300:4 3292:2 3288:B 3250:= 3245:) 3239:1 3232:y 3225:x 3219:( 3212:) 3206:F 3201:2 3197:/ 3193:E 3188:2 3184:/ 3180:D 3173:2 3169:/ 3165:E 3160:C 3155:2 3151:/ 3147:B 3140:2 3136:/ 3132:D 3127:2 3123:/ 3119:B 3114:A 3108:( 3101:) 3095:1 3090:y 3085:x 3079:( 3052:= 3049:F 3046:+ 3041:) 3035:y 3028:x 3022:( 3015:) 3009:E 3004:D 2998:( 2993:+ 2988:) 2982:y 2975:x 2969:( 2962:) 2956:C 2951:2 2947:/ 2943:B 2936:2 2932:/ 2928:B 2923:A 2917:( 2910:) 2904:y 2899:x 2893:( 2846:, 2843:0 2840:= 2837:F 2834:+ 2831:y 2828:E 2825:+ 2822:x 2819:D 2816:+ 2811:2 2807:y 2803:C 2800:+ 2797:y 2794:x 2791:B 2788:+ 2783:2 2779:x 2775:A 2726:. 2720:2 2716:c 2711:= 2708:d 2700:, 2696:) 2690:t 2687:d 2682:, 2679:t 2676:d 2672:( 2653:, 2641:) 2629:b 2626:, 2614:a 2608:( 2600:, 2597:) 2585:b 2582:, 2570:a 2567:( 2538:, 2535:) 2532:t 2529:a 2526:2 2523:, 2518:2 2514:t 2510:a 2507:( 2478:, 2475:) 2463:b 2460:, 2448:a 2445:( 2416:, 2413:) 2401:a 2398:, 2386:a 2383:( 2356:x 2352:y 2346:x 2342:y 2336:x 2330:y 2324:x 2304:. 2299:2 2295:c 2291:= 2288:y 2285:x 2259:, 2256:1 2253:= 2246:2 2242:b 2236:2 2232:y 2219:2 2215:a 2209:2 2205:x 2176:, 2173:0 2167:a 2159:, 2156:x 2153:a 2150:4 2147:= 2142:2 2138:y 2111:, 2108:1 2105:= 2098:2 2094:b 2088:2 2084:y 2078:+ 2071:2 2067:a 2061:2 2057:x 2028:, 2023:2 2019:a 2015:= 2010:2 2006:y 2002:+ 1997:2 1993:x 1976:) 1974:c 1970:c 1964:) 1962:c 1958:c 1956:( 1951:y 1947:x 1930:a 1926:x 1919:a 1917:( 1913:x 1908:b 1904:a 1900:r 1889:b 1885:a 1878:c 1872:b 1868:a 1864:c 1858:b 1854:a 1850:c 1845:b 1839:c 1831:a 1825:x 1756:2 1752:b 1748:+ 1743:2 1739:a 1732:2 1728:b 1702:a 1697:2 1693:b 1665:2 1661:b 1657:+ 1652:2 1648:a 1618:2 1614:a 1608:2 1604:b 1598:+ 1595:1 1572:1 1569:= 1562:2 1558:b 1552:2 1548:y 1535:2 1531:a 1525:2 1521:x 1489:a 1486:2 1464:a 1461:2 1436:1 1414:x 1411:a 1408:4 1405:= 1400:2 1396:y 1362:2 1358:b 1349:2 1345:a 1338:2 1334:b 1308:a 1303:2 1299:b 1271:2 1267:b 1258:2 1254:a 1224:2 1220:a 1214:2 1210:b 1201:1 1178:1 1175:= 1168:2 1164:b 1158:2 1154:y 1148:+ 1141:2 1137:a 1131:2 1127:x 1074:a 1052:0 1030:0 1006:2 1002:a 998:= 993:2 989:y 985:+ 980:2 976:x 955:p 946:ℓ 937:c 928:e 901:0 895:b 892:, 889:a 864:e 861:a 856:= 853:c 850:+ 847:p 823:e 820:a 817:= 814:c 790:e 787:p 784:= 762:b 758:b 754:b 752:( 739:a 733:a 731:( 725:a 719:x 715:a 713:( 698:p 696:( 687:ℓ 685:( 668:c 666:( 646:e 625:a 623:2 617:a 611:a 609:2 604:a 602:2 575:. 529:, 484:e 477:e 470:e 460:L 456:P 446:e 436:F 432:P 420:∞ 412:0 406:e 399:e 392:e 214:= 211:F 208:+ 205:y 202:E 199:+ 196:x 193:D 190:+ 185:2 181:y 177:C 174:+ 171:y 168:x 165:B 162:+ 157:2 153:x 149:A 20:)

Index

Conic sections


2D side view of cone being sectioned by planes at three different angles. The ellipse converges on the opposite side and so closes around the cone to form a closed profile. The hyperbola is parallel with the opposite side of the cone and so it never closes around it and the open ends extend to infinity. The hyperbola diverges from the opposite side. so it looks like the parabola but also has another part where it intersects with a mirror image of the cone
curve
cone's surface
plane
hyperbola
parabola
ellipse
circle
ancient Greek mathematicians
Apollonius of Perga
Euclidean plane
set
focus
eccentricity
analytic geometry
plane algebraic curve
quadratic equation
projective plane
real
complex

Circle
Ellipse
Parabola
Hyperbola
Euclidean geometry
plane

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