Knowledge

Small-angle approximation

Source 📝

323: 346: 1382: 2241: 394: 20: 1610: 3020: 162: 1392: 2231: 1133: 707: 2852: 1712: 2071: 51: 1371: 998: 595: 1716:
It is readily seen that the second most significant (third-order) term falls off as the cube of the first term; thus, even for a not-so-small argument such as 0.01, the value of the second most significant term is on the order of
322: 1605:{\displaystyle {\begin{aligned}\sin \theta &=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{(2n+1)!}}\theta ^{2n+1}\\&=\theta -{\frac {\theta ^{3}}{3!}}+{\frac {\theta ^{5}}{5!}}-{\frac {\theta ^{7}}{7!}}+\cdots \end{aligned}}} 2667: 944: 833: 1619: 315:
The accuracy of the approximations can be seen below in Figure 1 and Figure 2. As the measure of the angle approaches zero, the difference between the approximation and the original function also approaches 0.
1824: 756: 496: 345: 2062: 1191: 2545: 2857: 1397: 56: 2797: 2710:
of a simple pendulum, the small-angle approximation for sine is used to allow the resulting differential equation to be solved easily by comparison with the differential equation describing
982: 871: 2018: 1775: 1255: 3015:{\displaystyle {\begin{aligned}\sin(0.755)&=\sin(0.75+0.005)\\&\approx \sin(0.75)+(0.005)\cos(0.75)\\&\approx (0.6816)+(0.005)(0.7317)\\&\approx 0.6853.\end{aligned}}} 300: 240: 1898: 1977: 1951: 1864: 157:{\displaystyle {\begin{aligned}\sin \theta &\approx \theta \\\cos \theta &\approx 1-{\frac {\theta ^{2}}{2}}\approx 1\\\tan \theta &\approx \theta \end{aligned}}} 1918: 1284: 2806:
The small-angle approximation also appears in structural mechanics, especially in stability and bifurcation analyses (mainly of axially-loaded columns ready to undergo
2226:{\displaystyle \sin ^{2}(\theta \varepsilon )+\cos ^{2}(\theta \varepsilon )=(\theta \varepsilon )^{2}+1^{2}=\theta ^{2}\varepsilon ^{2}+1=\theta ^{2}\cdot 0+1=1} 1289: 260: 883: 772: 1782: 714: 447: 1128:{\displaystyle \lim _{\theta \to 0}{\frac {\cos(\theta )-1}{\theta ^{2}}}=\lim _{\theta \to 0}{\frac {-\sin(\theta )}{2\theta }}=-{\frac {1}{2}},} 702:{\displaystyle \sin \theta ={\frac {O}{H}}\approx {\frac {O}{A}}=\tan \theta ={\frac {O}{A}}\approx {\frac {s}{A}}={\frac {A\theta }{A}}=\theta .} 3176: 2593: 1198: 2255:
Figure 3 shows the relative errors of the small angle approximations. The angles at which the relative error exceeds 1% are as follows:
3022:
where the values for sin(0.75) and cos(0.75) are obtained from trigonometric table. The result is accurate to the four digits given.
2761: 206:
There are a number of ways to demonstrate the validity of the small-angle approximations. The most direct method is to truncate the
2023: 2329: 1748: 1138: 211: 1779:
By extension, since the cosine of a small angle is very nearly 1, and the tangent is given by the sine divided by the cosine,
3185: 1707:{\displaystyle \sin \theta =\theta -{\frac {\theta ^{3}}{6}}+{\frac {\theta ^{5}}{120}}-{\frac {\theta ^{7}}{5040}}+\cdots } 3104: 3077: 3036: 2499: 949: 838: 3253: 1982: 1203: 3212: 3155: 2810:). This leads to significant simplifications, though at a cost in accuracy and insight into the true behavior. 217: 265: 2826:
has its basis in the small-angle approximation, plus the fact that one radian is approximately 60 degrees.
1869: 1956: 1923: 1840: 992: 2481:(denoted by the symbol ″), so it is well suited to the small angle approximation. The linear size ( 1903: 1389:
The Maclaurin expansion (the Taylor expansion about 0) of the relevant trigonometric function is
3046: 38: 1260: 3228: 2735: 2723: 2711: 1381: 3248: 3202: 3145: 3094: 3067: 3041: 200: 1366:{\textstyle \cos \theta =1-2\sin ^{2}{\frac {\theta }{2}}\approx 1-{\frac {\theta ^{2}}{2}}} 2700: 2065: 8: 2843: 2739: 245: 3208: 3181: 3151: 3100: 3073: 3120: 2692: 207: 196: 180: 3031: 766: 2823: 2248: 2691:
The second-order cosine approximation is especially useful in calculating the
3242: 2839: 382:. It is seen that as the angle approaches 0 the approximation becomes better. 339:. It is seen that as the angle approaches 0 the approximations become better. 2734:
The sine and tangent small-angle approximations are used in relation to the
2240: 3171: 2819: 2474: 1834: 332: 188: 172: 19: 2746:
is the distance of a fringe from the center of maximum light intensity,
2477:
or angle subtended by the image of a distant object is often only a few
3072:(2nd ed.), Springer Science & Business Media, pp. 30–32, 939:{\displaystyle \lim _{\theta \to 0}{\frac {\tan(\theta )}{\theta }}=1,} 828:{\displaystyle \lim _{\theta \to 0}{\frac {\sin(\theta )}{\theta }}=1,} 393: 2662:{\displaystyle D=d\tan \left(X{\frac {2\pi }{1\,296\,000{''}}}\right)} 1979:. By using the MacLaurin series of cosine and sine, one can show that 2707: 2478: 2470: 192: 176: 2807: 2696: 23:
Approximately equal behavior of some (trigonometric) functions for
41:, provided that the angle in question is small and is measured in 168: 2722:
In optics, the small-angle approximations form the basis of the
1819:{\displaystyle \tan \theta \approx \sin \theta \approx \theta ,} 751:{\displaystyle \sin \theta \approx \tan \theta \approx \theta .} 491:{\displaystyle \cos {\theta }\approx 1-{\frac {\theta ^{2}}{2}}} 3121:"Small-Angle Approximation | Brilliant Math & Science Wiki" 2566: 184: 42: 880:
A more careful application of the squeeze theorem proves that
167:
These approximations have a wide range of uses in branches of
3147:
Calculus of a Single Variable: Early Transcendental Functions
2754:
is the distance between the slits and projection screen, and
2057:{\displaystyle \sin(\theta \varepsilon )=\theta \varepsilon } 1186:{\textstyle \cos(\theta )\approx 1-{\frac {\theta ^{2}}{2}}} 401:, is the difference between the lengths of the hypotenuse, 3099:(2nd ed.), McGraw-Hill Higher Education, p. 12, 2742:
to develop simplified equations like the following, where
210:
for each of the trigonometric functions. Depending on the
2332:
reduce to the following when one of the angles is small (
203:
that do not need to be answered with absolute precision.
2565:
is approximately equal to the number of arcseconds in a
504:, is approximately equal to the length of the blue arc, 199:. One reason for this is that they can greatly simplify 3065: 3143: 1292: 1141: 268: 221: 2855: 2764: 2596: 2502: 2074: 2026: 1985: 1959: 1926: 1906: 1872: 1843: 1785: 1751: 1622: 1395: 1263: 1206: 1001: 952: 886: 841: 775: 717: 598: 450: 248: 220: 54: 1385:
The small-angle approximation for the sine function.
835:which is a formal restatement of the approximation 16:
Simplification of the basic trigonometric functions
3092: 3014: 2791: 2703:to find the indirect (energy) equation of motion. 2661: 2539: 2225: 2056: 2012: 1971: 1945: 1912: 1892: 1858: 1818: 1769: 1745:the first term. One can thus safely approximate: 1706: 1604: 1365: 1278: 1249: 1185: 1127: 976: 938: 865: 827: 750: 701: 490: 294: 254: 234: 156: 37:can be used to approximate the values of the main 3240: 2836:addition and subtraction involving a small angle 2792:{\displaystyle y\approx {\frac {m\lambda D}{d}}} 2064:. Furthermore, it is not hard to prove that the 1059: 1003: 888: 777: 3150:(4th ed.), Cengage Learning, p. 85, 2235: 3177:Mathematical Methods in the Physical Sciences 2835: 2584:, or, the number of arcseconds in 1 radian. 2540:{\displaystyle D=X{\frac {d}{206\,265{''}}}} 1616:is the angle in radians. In clearer terms, 977:{\displaystyle \tan(\theta )\approx \theta } 866:{\displaystyle \sin(\theta )\approx \theta } 3096:Engineering Mechanics: Statics and Dynamics 2323: 2013:{\displaystyle \cos(\theta \varepsilon )=1} 1770:{\displaystyle \sin \theta \approx \theta } 1250:{\displaystyle \cos 2A\equiv 1-2\sin ^{2}A} 3207:, Cambridge University Press, p. 19, 3059: 3137: 3086: 3066:Holbrow, Charles H.; et al. (2010), 2672:and the above approximation follows when 2638: 2634: 2521: 1886: 3194: 2239: 1380: 18: 2801: 2686: 2330:angle addition and subtraction theorems 295:{\textstyle 1-{\frac {\theta ^{2}}{2}}} 235:{\displaystyle \textstyle \cos \theta } 3241: 2489:) and the distance from the observer ( 3200: 3093:Plesha, Michael; et al. (2012), 3170: 2729: 417:are almost the same length, meaning 2758:is the distance between the slits: 2699:, which can then be applied with a 2251:for the small angle approximations. 1893:{\displaystyle a,b\in \mathbb {R} } 13: 2485:) is related to the angular size ( 1972:{\displaystyle \varepsilon \neq 0} 1946:{\displaystyle \varepsilon ^{2}=0} 1432: 14: 3265: 3144:Larson, Ron; et al. (2006), 1837:, defined as numbers in the form 508:. Gathering facts from geometry, 305: 3037:Small oscillations of a pendulum 2829: 2459: 2319:at about 0.6620 radians (37.93°) 2292:at about 0.2441 radians (13.99°) 1197:. Alternatively, we can use the 392: 344: 321: 2279:at about 0.1730 radians (9.91°) 2266:at about 0.1408 radians (8.07°) 1859:{\displaystyle a+b\varepsilon } 1828: 3221: 3164: 3113: 2992: 2986: 2983: 2977: 2971: 2965: 2952: 2946: 2937: 2931: 2925: 2919: 2900: 2888: 2872: 2866: 2141: 2131: 2125: 2116: 2097: 2088: 2042: 2033: 2001: 1992: 1476: 1461: 1450: 1440: 1154: 1148: 1092: 1086: 1066: 1033: 1027: 1010: 965: 959: 918: 912: 895: 854: 848: 807: 801: 784: 397:The red section on the right, 1: 3052: 2750:is the order of the fringe, 2464: 1913:{\displaystyle \varepsilon } 1376: 946:from which we conclude that 387: 7: 3069:Modern Introductory Physics 3025: 2813: 2554:is measured in arcseconds. 2236:Error of the approximations 760: 335:trigonometric functions to 10: 3270: 1279:{\displaystyle \theta =2A} 331:A comparison of the basic 310: 242:is approximated as either 212:order of the approximation 35:small-angle approximations 2717: 2493:) by the simple formula: 1920:satisfying by definition 444:helps trim the red away. 405:, and the adjacent side, 3201:Green, Robin M. (1985), 2324:Angle sum and difference 572:, and from the picture, 3047:Exsecant and excosecant 39:trigonometric functions 3254:Equations of astronomy 3016: 2793: 2736:double-slit experiment 2724:paraxial approximation 2712:simple harmonic motion 2663: 2541: 2252: 2227: 2058: 2014: 1973: 1947: 1914: 1894: 1860: 1820: 1771: 1708: 1606: 1436: 1386: 1367: 1280: 1251: 1187: 1129: 978: 940: 867: 829: 752: 703: 492: 296: 256: 236: 201:differential equations 158: 30: 3180:. Wiley. p. 26. 3042:Versine and haversine 3017: 2794: 2706:When calculating the 2664: 2587:The exact formula is 2542: 2243: 2228: 2059: 2015: 1974: 1948: 1915: 1895: 1861: 1821: 1772: 1709: 1607: 1416: 1384: 1368: 1281: 1252: 1188: 1130: 979: 941: 868: 830: 753: 704: 518:, from trigonometry, 493: 297: 257: 237: 159: 22: 2853: 2849:Example: sin(0.755) 2802:Structural mechanics 2762: 2687:Motion of a pendulum 2594: 2500: 2072: 2066:Pythagorean identity 2024: 1983: 1957: 1924: 1904: 1870: 1841: 1783: 1749: 1620: 1393: 1290: 1261: 1204: 1199:double angle formula 1193:for small values of 1139: 1135:which rearranges to 999: 984:for small values of 950: 884: 873:for small values of 839: 773: 769:, we can prove that 715: 711:Simplifying leaves, 596: 448: 266: 246: 218: 52: 3229:"Slit Interference" 3204:Spherical Astronomy 2844:trigonometric table 2740:diffraction grating 3012: 3010: 2789: 2659: 2537: 2253: 2223: 2054: 2010: 1969: 1943: 1910: 1890: 1856: 1816: 1767: 1704: 1602: 1600: 1387: 1363: 1276: 1247: 1183: 1125: 1073: 1017: 974: 936: 902: 863: 825: 791: 748: 699: 500:The opposite leg, 488: 424:is close to 1 and 292: 252: 232: 231: 154: 152: 31: 3187:978-0-471-19826-0 2834:The formulas for 2787: 2730:Wave Interference 2652: 2535: 2455: 2454: 1833:One may also use 1696: 1676: 1656: 1590: 1565: 1540: 1483: 1361: 1335: 1181: 1120: 1104: 1058: 1053: 1002: 925: 887: 814: 776: 688: 670: 657: 632: 619: 486: 290: 255:{\displaystyle 1} 119: 3261: 3233: 3232: 3225: 3219: 3218: 3198: 3192: 3191: 3168: 3162: 3161: 3141: 3135: 3134: 3132: 3131: 3117: 3111: 3110: 3090: 3084: 3083: 3063: 3021: 3019: 3018: 3013: 3011: 2998: 2958: 2906: 2838:may be used for 2798: 2796: 2795: 2790: 2788: 2783: 2772: 2757: 2753: 2749: 2745: 2693:potential energy 2682: 2678: 2668: 2666: 2665: 2660: 2658: 2654: 2653: 2651: 2650: 2649: 2629: 2621: 2583: 2579: 2577: 2574: 2564: 2562: 2553: 2546: 2544: 2543: 2538: 2536: 2534: 2533: 2532: 2513: 2492: 2488: 2484: 2341: 2340: 2318: 2317: 2315: 2314: 2311: 2308: 2291: 2278: 2265: 2232: 2230: 2229: 2224: 2204: 2203: 2185: 2184: 2175: 2174: 2162: 2161: 2149: 2148: 2112: 2111: 2084: 2083: 2063: 2061: 2060: 2055: 2019: 2017: 2016: 2011: 1978: 1976: 1975: 1970: 1952: 1950: 1949: 1944: 1936: 1935: 1919: 1917: 1916: 1911: 1899: 1897: 1896: 1891: 1889: 1865: 1863: 1862: 1857: 1825: 1823: 1822: 1817: 1776: 1774: 1773: 1768: 1744: 1742: 1741: 1740: 1739: 1733: 1730: 1723: 1722: 1713: 1711: 1710: 1705: 1697: 1692: 1691: 1682: 1677: 1672: 1671: 1662: 1657: 1652: 1651: 1642: 1615: 1611: 1609: 1608: 1603: 1601: 1591: 1589: 1581: 1580: 1571: 1566: 1564: 1556: 1555: 1546: 1541: 1539: 1531: 1530: 1521: 1507: 1503: 1502: 1484: 1482: 1459: 1458: 1457: 1438: 1435: 1430: 1372: 1370: 1369: 1364: 1362: 1357: 1356: 1347: 1336: 1328: 1323: 1322: 1285: 1283: 1282: 1277: 1256: 1254: 1253: 1248: 1240: 1239: 1192: 1190: 1189: 1184: 1182: 1177: 1176: 1167: 1134: 1132: 1131: 1126: 1121: 1113: 1105: 1103: 1095: 1075: 1072: 1054: 1052: 1051: 1042: 1019: 1016: 993:L'Hôpital's rule 983: 981: 980: 975: 945: 943: 942: 937: 926: 921: 904: 901: 872: 870: 869: 864: 834: 832: 831: 826: 815: 810: 793: 790: 757: 755: 754: 749: 708: 706: 705: 700: 689: 684: 676: 671: 663: 658: 650: 633: 625: 620: 612: 591: 581: 571: 570: 568: 567: 562: 559: 544: 543: 541: 540: 535: 532: 517: 507: 503: 497: 495: 494: 489: 487: 482: 481: 472: 461: 443: 442: 440: 439: 436: 433: 423: 416: 412: 408: 404: 400: 396: 381: 380: 378: 377: 374: 371: 360: 354:A comparison of 348: 338: 325: 301: 299: 298: 293: 291: 286: 285: 276: 261: 259: 258: 253: 241: 239: 238: 233: 208:Maclaurin series 197:computer science 181:electromagnetism 163: 161: 160: 155: 153: 120: 115: 114: 105: 29: 3269: 3268: 3264: 3263: 3262: 3260: 3259: 3258: 3239: 3238: 3237: 3236: 3227: 3226: 3222: 3215: 3199: 3195: 3188: 3169: 3165: 3158: 3142: 3138: 3129: 3127: 3119: 3118: 3114: 3107: 3091: 3087: 3080: 3064: 3060: 3055: 3032:Skinny triangle 3028: 3009: 3008: 2996: 2995: 2956: 2955: 2904: 2903: 2875: 2856: 2854: 2851: 2850: 2832: 2816: 2804: 2773: 2771: 2763: 2760: 2759: 2755: 2751: 2747: 2743: 2732: 2720: 2689: 2680: 2679:is replaced by 2673: 2643: 2642: 2630: 2622: 2620: 2616: 2612: 2595: 2592: 2591: 2581: 2575: 2572: 2570: 2560: 2558: 2551: 2526: 2525: 2517: 2512: 2501: 2498: 2497: 2490: 2486: 2482: 2467: 2462: 2326: 2312: 2309: 2304: 2303: 2301: 2295: 2282: 2269: 2259: 2249:relative errors 2247:A graph of the 2238: 2199: 2195: 2180: 2176: 2170: 2166: 2157: 2153: 2144: 2140: 2107: 2103: 2079: 2075: 2073: 2070: 2069: 2025: 2022: 2021: 1984: 1981: 1980: 1958: 1955: 1954: 1931: 1927: 1925: 1922: 1921: 1905: 1902: 1901: 1885: 1871: 1868: 1867: 1842: 1839: 1838: 1831: 1784: 1781: 1780: 1750: 1747: 1746: 1737: 1735: 1734: 1731: 1728: 1727: 1725: 1720: 1718: 1687: 1683: 1681: 1667: 1663: 1661: 1647: 1643: 1641: 1621: 1618: 1617: 1613: 1599: 1598: 1582: 1576: 1572: 1570: 1557: 1551: 1547: 1545: 1532: 1526: 1522: 1520: 1505: 1504: 1489: 1485: 1460: 1453: 1449: 1439: 1437: 1431: 1420: 1409: 1396: 1394: 1391: 1390: 1379: 1352: 1348: 1346: 1327: 1318: 1314: 1291: 1288: 1287: 1262: 1259: 1258: 1235: 1231: 1205: 1202: 1201: 1172: 1168: 1166: 1140: 1137: 1136: 1112: 1096: 1076: 1074: 1062: 1047: 1043: 1020: 1018: 1006: 1000: 997: 996: 951: 948: 947: 905: 903: 891: 885: 882: 881: 840: 837: 836: 794: 792: 780: 774: 771: 770: 767:squeeze theorem 763: 716: 713: 712: 677: 675: 662: 649: 624: 611: 597: 594: 593: 583: 573: 563: 560: 555: 554: 552: 546: 536: 533: 528: 527: 525: 519: 509: 505: 501: 477: 473: 471: 457: 449: 446: 445: 437: 434: 429: 428: 426: 425: 418: 414: 410: 409:. As is shown, 406: 402: 398: 390: 383: 375: 372: 367: 366: 364: 362: 355: 349: 340: 336: 326: 313: 308: 281: 277: 275: 267: 264: 263: 247: 244: 243: 219: 216: 215: 151: 150: 140: 128: 127: 110: 106: 104: 91: 79: 78: 68: 55: 53: 50: 49: 24: 17: 12: 11: 5: 3267: 3257: 3256: 3251: 3235: 3234: 3220: 3213: 3193: 3186: 3163: 3156: 3136: 3112: 3106:978-0077570613 3105: 3085: 3079:978-0387790794 3078: 3057: 3056: 3054: 3051: 3050: 3049: 3044: 3039: 3034: 3027: 3024: 3007: 3004: 3001: 2999: 2997: 2994: 2991: 2988: 2985: 2982: 2979: 2976: 2973: 2970: 2967: 2964: 2961: 2959: 2957: 2954: 2951: 2948: 2945: 2942: 2939: 2936: 2933: 2930: 2927: 2924: 2921: 2918: 2915: 2912: 2909: 2907: 2905: 2902: 2899: 2896: 2893: 2890: 2887: 2884: 2881: 2878: 2876: 2874: 2871: 2868: 2865: 2862: 2859: 2858: 2831: 2828: 2824:air navigation 2815: 2812: 2803: 2800: 2786: 2782: 2779: 2776: 2770: 2767: 2731: 2728: 2719: 2716: 2688: 2685: 2670: 2669: 2657: 2648: 2645: 2641: 2637: 2633: 2628: 2625: 2619: 2615: 2611: 2608: 2605: 2602: 2599: 2580:), divided by 2548: 2547: 2531: 2528: 2524: 2520: 2516: 2511: 2508: 2505: 2466: 2463: 2461: 2458: 2457: 2456: 2453: 2452: 2437: 2425: 2424: 2409: 2397: 2396: 2381: 2369: 2368: 2353: 2325: 2322: 2321: 2320: 2293: 2280: 2267: 2237: 2234: 2222: 2219: 2216: 2213: 2210: 2207: 2202: 2198: 2194: 2191: 2188: 2183: 2179: 2173: 2169: 2165: 2160: 2156: 2152: 2147: 2143: 2139: 2136: 2133: 2130: 2127: 2124: 2121: 2118: 2115: 2110: 2106: 2102: 2099: 2096: 2093: 2090: 2087: 2082: 2078: 2053: 2050: 2047: 2044: 2041: 2038: 2035: 2032: 2029: 2009: 2006: 2003: 2000: 1997: 1994: 1991: 1988: 1968: 1965: 1962: 1942: 1939: 1934: 1930: 1909: 1888: 1884: 1881: 1878: 1875: 1855: 1852: 1849: 1846: 1830: 1827: 1815: 1812: 1809: 1806: 1803: 1800: 1797: 1794: 1791: 1788: 1766: 1763: 1760: 1757: 1754: 1703: 1700: 1695: 1690: 1686: 1680: 1675: 1670: 1666: 1660: 1655: 1650: 1646: 1640: 1637: 1634: 1631: 1628: 1625: 1597: 1594: 1588: 1585: 1579: 1575: 1569: 1563: 1560: 1554: 1550: 1544: 1538: 1535: 1529: 1525: 1519: 1516: 1513: 1510: 1508: 1506: 1501: 1498: 1495: 1492: 1488: 1481: 1478: 1475: 1472: 1469: 1466: 1463: 1456: 1452: 1448: 1445: 1442: 1434: 1429: 1426: 1423: 1419: 1415: 1412: 1410: 1408: 1405: 1402: 1399: 1398: 1378: 1375: 1360: 1355: 1351: 1345: 1342: 1339: 1334: 1331: 1326: 1321: 1317: 1313: 1310: 1307: 1304: 1301: 1298: 1295: 1286:, we get that 1275: 1272: 1269: 1266: 1246: 1243: 1238: 1234: 1230: 1227: 1224: 1221: 1218: 1215: 1212: 1209: 1180: 1175: 1171: 1165: 1162: 1159: 1156: 1153: 1150: 1147: 1144: 1124: 1119: 1116: 1111: 1108: 1102: 1099: 1094: 1091: 1088: 1085: 1082: 1079: 1071: 1068: 1065: 1061: 1057: 1050: 1046: 1041: 1038: 1035: 1032: 1029: 1026: 1023: 1015: 1012: 1009: 1005: 995:tells us that 973: 970: 967: 964: 961: 958: 955: 935: 932: 929: 924: 920: 917: 914: 911: 908: 900: 897: 894: 890: 862: 859: 856: 853: 850: 847: 844: 824: 821: 818: 813: 809: 806: 803: 800: 797: 789: 786: 783: 779: 762: 759: 747: 744: 741: 738: 735: 732: 729: 726: 723: 720: 698: 695: 692: 687: 683: 680: 674: 669: 666: 661: 656: 653: 648: 645: 642: 639: 636: 631: 628: 623: 618: 615: 610: 607: 604: 601: 485: 480: 476: 470: 467: 464: 460: 456: 453: 389: 386: 385: 384: 350: 343: 341: 327: 320: 312: 309: 307: 306:Justifications 304: 289: 284: 280: 274: 271: 251: 230: 227: 224: 165: 164: 149: 146: 143: 141: 139: 136: 133: 130: 129: 126: 123: 118: 113: 109: 103: 100: 97: 94: 92: 90: 87: 84: 81: 80: 77: 74: 71: 69: 67: 64: 61: 58: 57: 15: 9: 6: 4: 3: 2: 3266: 3255: 3252: 3250: 3247: 3246: 3244: 3230: 3224: 3216: 3210: 3206: 3205: 3197: 3189: 3183: 3179: 3178: 3173: 3172:Boas, Mary L. 3167: 3159: 3153: 3149: 3148: 3140: 3126: 3125:brilliant.org 3122: 3116: 3108: 3102: 3098: 3097: 3089: 3081: 3075: 3071: 3070: 3062: 3058: 3048: 3045: 3043: 3040: 3038: 3035: 3033: 3030: 3029: 3023: 3005: 3002: 3000: 2989: 2980: 2974: 2968: 2962: 2960: 2949: 2943: 2940: 2934: 2928: 2922: 2916: 2913: 2910: 2908: 2897: 2894: 2891: 2885: 2882: 2879: 2877: 2869: 2863: 2860: 2847: 2845: 2841: 2840:interpolating 2837: 2830:Interpolation 2827: 2825: 2821: 2811: 2809: 2799: 2784: 2780: 2777: 2774: 2768: 2765: 2741: 2737: 2727: 2725: 2715: 2713: 2709: 2704: 2702: 2698: 2694: 2684: 2677: 2655: 2646: 2644: 2639: 2635: 2631: 2626: 2623: 2617: 2613: 2609: 2606: 2603: 2600: 2597: 2590: 2589: 2588: 2585: 2568: 2557:The quantity 2555: 2529: 2527: 2522: 2518: 2514: 2509: 2506: 2503: 2496: 2495: 2494: 2480: 2476: 2472: 2460:Specific uses 2450: 2446: 2442: 2438: 2435: 2431: 2427: 2426: 2422: 2418: 2414: 2410: 2407: 2403: 2399: 2398: 2394: 2390: 2386: 2382: 2379: 2375: 2371: 2370: 2366: 2362: 2358: 2354: 2351: 2347: 2343: 2342: 2339: 2338: 2337: 2335: 2331: 2307: 2299: 2294: 2290: 2286: 2281: 2277: 2273: 2268: 2263: 2258: 2257: 2256: 2250: 2246: 2242: 2233: 2220: 2217: 2214: 2211: 2208: 2205: 2200: 2196: 2192: 2189: 2186: 2181: 2177: 2171: 2167: 2163: 2158: 2154: 2150: 2145: 2137: 2134: 2128: 2122: 2119: 2113: 2108: 2104: 2100: 2094: 2091: 2085: 2080: 2076: 2067: 2051: 2048: 2045: 2039: 2036: 2030: 2027: 2007: 2004: 1998: 1995: 1989: 1986: 1966: 1963: 1960: 1940: 1937: 1932: 1928: 1907: 1882: 1879: 1876: 1873: 1853: 1850: 1847: 1844: 1836: 1826: 1813: 1810: 1807: 1804: 1801: 1798: 1795: 1792: 1789: 1786: 1777: 1764: 1761: 1758: 1755: 1752: 1714: 1701: 1698: 1693: 1688: 1684: 1678: 1673: 1668: 1664: 1658: 1653: 1648: 1644: 1638: 1635: 1632: 1629: 1626: 1623: 1595: 1592: 1586: 1583: 1577: 1573: 1567: 1561: 1558: 1552: 1548: 1542: 1536: 1533: 1527: 1523: 1517: 1514: 1511: 1509: 1499: 1496: 1493: 1490: 1486: 1479: 1473: 1470: 1467: 1464: 1454: 1446: 1443: 1427: 1424: 1421: 1417: 1413: 1411: 1406: 1403: 1400: 1383: 1374: 1358: 1353: 1349: 1343: 1340: 1337: 1332: 1329: 1324: 1319: 1315: 1311: 1308: 1305: 1302: 1299: 1296: 1293: 1273: 1270: 1267: 1264: 1257:. By letting 1244: 1241: 1236: 1232: 1228: 1225: 1222: 1219: 1216: 1213: 1210: 1207: 1200: 1196: 1178: 1173: 1169: 1163: 1160: 1157: 1151: 1145: 1142: 1122: 1117: 1114: 1109: 1106: 1100: 1097: 1089: 1083: 1080: 1077: 1069: 1063: 1055: 1048: 1044: 1039: 1036: 1030: 1024: 1021: 1013: 1007: 994: 989: 987: 971: 968: 962: 956: 953: 933: 930: 927: 922: 915: 909: 906: 898: 892: 878: 876: 860: 857: 851: 845: 842: 822: 819: 816: 811: 804: 798: 795: 787: 781: 768: 758: 745: 742: 739: 736: 733: 730: 727: 724: 721: 718: 709: 696: 693: 690: 685: 681: 678: 672: 667: 664: 659: 654: 651: 646: 643: 640: 637: 634: 629: 626: 621: 616: 613: 608: 605: 602: 599: 590: 586: 580: 576: 566: 558: 550: 539: 531: 523: 516: 512: 498: 483: 478: 474: 468: 465: 462: 458: 454: 451: 432: 422: 395: 370: 359: 353: 347: 342: 334: 330: 324: 319: 318: 317: 303: 287: 282: 278: 272: 269: 249: 228: 225: 222: 213: 209: 204: 202: 198: 194: 190: 186: 182: 178: 174: 170: 147: 144: 142: 137: 134: 131: 124: 121: 116: 111: 107: 101: 98: 95: 93: 88: 85: 82: 75: 72: 70: 65: 62: 59: 48: 47: 46: 44: 40: 36: 27: 21: 3249:Trigonometry 3223: 3203: 3196: 3175: 3166: 3146: 3139: 3128:. Retrieved 3124: 3115: 3095: 3088: 3068: 3061: 2848: 2833: 2820:1 in 60 rule 2817: 2805: 2733: 2721: 2705: 2690: 2675: 2671: 2586: 2556: 2549: 2475:angular size 2468: 2448: 2444: 2440: 2433: 2429: 2420: 2416: 2412: 2405: 2401: 2392: 2388: 2384: 2377: 2373: 2364: 2360: 2356: 2349: 2345: 2333: 2327: 2305: 2297: 2288: 2284: 2275: 2271: 2261: 2254: 2244: 1835:dual numbers 1832: 1829:Dual numbers 1778: 1715: 1388: 1194: 990: 985: 879: 874: 764: 710: 588: 584: 578: 574: 564: 556: 548: 537: 529: 521: 514: 510: 499: 430: 420: 391: 368: 357: 351: 328: 314: 205: 175:, including 166: 34: 32: 25: 189:cartography 173:engineering 3243:Categories 3214:0521317797 3157:0618606254 3130:2020-07-22 3053:References 2701:Lagrangian 2479:arcseconds 765:Using the 592:leads to: 3003:≈ 2963:≈ 2944:⁡ 2917:⁡ 2911:≈ 2886:⁡ 2864:⁡ 2778:λ 2769:≈ 2627:π 2610:⁡ 2471:astronomy 2465:Astronomy 2245:Figure 3. 2206:⋅ 2197:θ 2178:ε 2168:θ 2138:ε 2135:θ 2123:ε 2120:θ 2114:⁡ 2095:ε 2092:θ 2086:⁡ 2052:ε 2049:θ 2040:ε 2037:θ 2031:⁡ 1999:ε 1996:θ 1990:⁡ 1964:≠ 1961:ε 1929:ε 1908:ε 1883:∈ 1854:ε 1811:θ 1808:≈ 1805:θ 1802:⁡ 1796:≈ 1793:θ 1790:⁡ 1765:θ 1762:≈ 1759:θ 1756:⁡ 1702:⋯ 1685:θ 1679:− 1665:θ 1645:θ 1639:− 1636:θ 1630:θ 1627:⁡ 1596:⋯ 1574:θ 1568:− 1549:θ 1524:θ 1518:− 1515:θ 1487:θ 1444:− 1433:∞ 1418:∑ 1407:θ 1404:⁡ 1377:Algebraic 1350:θ 1344:− 1338:≈ 1330:θ 1325:⁡ 1309:− 1300:θ 1297:⁡ 1265:θ 1242:⁡ 1226:− 1220:≡ 1211:⁡ 1170:θ 1164:− 1158:≈ 1152:θ 1146:⁡ 1110:− 1101:θ 1090:θ 1084:⁡ 1078:− 1067:→ 1064:θ 1045:θ 1037:− 1031:θ 1025:⁡ 1011:→ 1008:θ 991:Finally, 972:θ 969:≈ 963:θ 957:⁡ 923:θ 916:θ 910:⁡ 896:→ 893:θ 861:θ 858:≈ 852:θ 846:⁡ 812:θ 805:θ 799:⁡ 785:→ 782:θ 743:θ 740:≈ 737:θ 734:⁡ 728:≈ 725:θ 722:⁡ 694:θ 682:θ 660:≈ 644:θ 641:⁡ 622:≈ 606:θ 603:⁡ 475:θ 469:− 463:≈ 459:θ 455:⁡ 388:Geometric 352:Figure 2. 329:Figure 1. 279:θ 273:− 229:θ 226:⁡ 193:astronomy 177:mechanics 148:θ 145:≈ 138:θ 135:⁡ 122:≈ 108:θ 102:− 96:≈ 89:θ 86:⁡ 76:θ 73:≈ 66:θ 63:⁡ 3174:(2006). 3026:See also 2846:values: 2842:between 2822:used in 2814:Piloting 2808:buckling 2697:pendulum 2647:″ 2530:″ 761:Calculus 3006:0.6853. 2316:⁠ 2302:⁠ 1866:, with 1743:⁠ 1726:⁠ 569:⁠ 553:⁠ 542:⁠ 526:⁠ 441:⁠ 427:⁠ 379:⁠ 365:⁠ 311:Graphic 169:physics 43:radians 3211:  3184:  3154:  3103:  3076:  2990:0.7317 2969:0.6816 2718:Optics 2708:period 2567:circle 2550:where 2473:, the 2439:≈ sin( 2411:≈ sin( 2383:≈ cos( 2355:≈ cos( 2336:≈ 0): 2300:≈ 1 − 2068:holds: 1612:where 262:or as 195:, and 185:optics 2981:0.005 2935:0.005 2898:0.005 2870:0.755 2738:or a 2695:of a 1724:, or 1719:0.000 3209:ISBN 3182:ISBN 3152:ISBN 3101:ISBN 3074:ISBN 2950:0.75 2923:0.75 2892:0.75 2818:The 2674:tan 2447:cos( 2443:) − 2428:sin( 2419:cos( 2415:) + 2400:sin( 2391:sin( 2387:) + 2372:cos( 2363:sin( 2359:) − 2344:cos( 2328:The 2296:cos 2283:sin 2270:tan 2260:cos 2020:and 1953:and 1900:and 1694:5040 582:and 547:tan 545:and 520:sin 419:cos 413:and 363:1 − 356:cos 171:and 33:The 2941:cos 2914:sin 2883:sin 2861:sin 2640:000 2636:296 2607:tan 2576:000 2573:296 2561:265 2559:206 2523:265 2519:206 2469:In 2451:). 2423:), 2395:), 2367:), 2264:≈ 1 2105:cos 2077:sin 2028:sin 1987:cos 1799:sin 1787:tan 1753:sin 1738:000 1721:001 1674:120 1624:sin 1401:sin 1316:sin 1294:cos 1233:sin 1208:cos 1143:cos 1081:sin 1060:lim 1022:cos 1004:lim 954:tan 907:tan 889:lim 843:sin 796:sin 778:lim 731:tan 719:sin 638:tan 600:sin 452:cos 361:to 333:odd 223:cos 132:tan 83:cos 60:sin 28:→ 0 3245:: 3123:. 2726:. 2714:. 2683:. 2582:2π 2432:− 2404:+ 2376:− 2348:+ 2287:≈ 2274:≈ 1736:10 1373:. 988:. 877:. 587:≈ 577:≈ 551:= 524:= 515:Aθ 513:= 302:. 214:, 191:, 187:, 183:, 179:, 45:: 3231:. 3217:. 3190:. 3160:. 3133:. 3109:. 3082:. 2993:) 2987:( 2984:) 2978:( 2975:+ 2972:) 2966:( 2953:) 2947:( 2938:) 2932:( 2929:+ 2926:) 2920:( 2901:) 2895:+ 2889:( 2880:= 2873:) 2867:( 2785:d 2781:D 2775:m 2766:y 2756:d 2752:D 2748:m 2744:y 2681:X 2676:X 2656:) 2632:1 2624:2 2618:X 2614:( 2604:d 2601:= 2598:D 2578:″ 2571:1 2569:( 2563:″ 2552:X 2515:d 2510:X 2507:= 2504:D 2491:d 2487:X 2483:D 2449:α 2445:β 2441:α 2436:) 2434:β 2430:α 2421:α 2417:β 2413:α 2408:) 2406:β 2402:α 2393:α 2389:β 2385:α 2380:) 2378:β 2374:α 2365:α 2361:β 2357:α 2352:) 2350:β 2346:α 2334:β 2313:2 2310:/ 2306:θ 2298:θ 2289:θ 2285:θ 2276:θ 2272:θ 2262:θ 2221:1 2218:= 2215:1 2212:+ 2209:0 2201:2 2193:= 2190:1 2187:+ 2182:2 2172:2 2164:= 2159:2 2155:1 2151:+ 2146:2 2142:) 2132:( 2129:= 2126:) 2117:( 2109:2 2101:+ 2098:) 2089:( 2081:2 2046:= 2043:) 2034:( 2008:1 2005:= 2002:) 1993:( 1967:0 1941:0 1938:= 1933:2 1887:R 1880:b 1877:, 1874:a 1851:b 1848:+ 1845:a 1814:, 1732:/ 1729:1 1699:+ 1689:7 1669:5 1659:+ 1654:6 1649:3 1633:= 1614:θ 1593:+ 1587:! 1584:7 1578:7 1562:! 1559:5 1553:5 1543:+ 1537:! 1534:3 1528:3 1512:= 1500:1 1497:+ 1494:n 1491:2 1480:! 1477:) 1474:1 1471:+ 1468:n 1465:2 1462:( 1455:n 1451:) 1447:1 1441:( 1428:0 1425:= 1422:n 1414:= 1359:2 1354:2 1341:1 1333:2 1320:2 1312:2 1306:1 1303:= 1274:A 1271:2 1268:= 1245:A 1237:2 1229:2 1223:1 1217:A 1214:2 1195:θ 1179:2 1174:2 1161:1 1155:) 1149:( 1123:, 1118:2 1115:1 1107:= 1098:2 1093:) 1087:( 1070:0 1056:= 1049:2 1040:1 1034:) 1028:( 1014:0 986:θ 966:) 960:( 934:, 931:1 928:= 919:) 913:( 899:0 875:θ 855:) 849:( 823:, 820:1 817:= 808:) 802:( 788:0 746:. 697:. 691:= 686:A 679:A 673:= 668:A 665:s 655:A 652:O 647:= 635:= 630:A 627:O 617:H 614:O 609:= 589:A 585:H 579:s 575:O 565:A 561:/ 557:O 549:θ 538:H 534:/ 530:O 522:θ 511:s 506:s 502:O 484:2 479:2 466:1 438:2 435:/ 431:θ 421:θ 415:A 411:H 407:A 403:H 399:d 376:2 373:/ 369:θ 358:θ 337:θ 288:2 283:2 270:1 250:1 125:1 117:2 112:2 99:1 26:x

Index


trigonometric functions
radians
physics
engineering
mechanics
electromagnetism
optics
cartography
astronomy
computer science
differential equations
Maclaurin series
order of the approximation
Figure 1. A comparison of the basic odd trigonometric functions to θ. It is seen that as the angle approaches 0 the approximations become better.
odd
Figure 2. A comparison of cos θ to 1 − ⁠θ2/2⁠. It is seen that as the angle approaches 0 the approximation becomes better.

squeeze theorem
L'Hôpital's rule
double angle formula

dual numbers
Pythagorean identity

relative errors
angle addition and subtraction theorems
astronomy
angular size
arcseconds

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.