Knowledge

Spherical law of cosines

Source 📝

47: 2106: 2389: 1793: 1534: 2115: 1784: 2101:{\displaystyle 1-{\frac {c^{2}}{2}}+O\left(c^{4}\right)=1-{\frac {a^{2}}{2}}-{\frac {b^{2}}{2}}+{\frac {a^{2}b^{2}}{4}}+O\left(a^{4}\right)+O\left(b^{4}\right)+\cos(C)\left(ab+O\left(a^{3}b\right)+O\left(ab^{3}\right)+O\left(a^{3}b^{3}\right)\right)} 2589: 1366: 1654: 966: 450: 216: 2384:{\displaystyle c^{2}=a^{2}+b^{2}-2ab\cos C+O\left(c^{4}\right)+O\left(a^{4}\right)+O\left(b^{4}\right)+O\left(a^{2}b^{2}\right)+O\left(a^{3}b\right)+O\left(ab^{3}\right)+O\left(a^{3}b^{3}\right).} 1639: 1659: 1371: 1060: 2445: 515:
from the center of the sphere to those corners of the triangle. The angles and distances do not change if the coordinate system is rotated, so we can rotate the coordinate system so that
747: 656: 843: 338: 865: 769: 682: 591: 561: 535: 240:) subtended by those sides from the center of the sphere. (For a non-unit sphere, the lengths are the subtended angles times the radius, and the formula still holds if 992: 1529:{\displaystyle {\begin{aligned}\cos C&={\frac {\cos c-\cos a\cos b}{\sin a\sin b}}\\\cos c&={\frac {\cos C+\cos A\cos B}{\sin A\sin B}}\\\end{aligned}}} 374: 143: 1566: 2671: 1779:{\displaystyle {\begin{aligned}\cos a&=1-{\frac {a^{2}}{2}}+O\left(a^{4}\right)\\\sin a&=a+O\left(a^{3}\right)\end{aligned}}} 870: 295: 997: 2740: 687: 596: 2599: 774: 479: 2745: 2584:{\displaystyle c^{2}=a^{2}+b^{2}-2ab\cos C+O\left(a^{4}\right)+O\left(b^{4}\right)+O\left(c^{4}\right).} 2624: 1644: 1273: 848: 752: 665: 662:
is the angle measured from the north pole not from the equator, and the spherical coordinates for
574: 544: 518: 1563:, the spherical law of cosines is approximately the same as the ordinary planar law of cosines, 2634: 20: 2629: 2598:
Something equivalent to the spherical law of cosines was used (but not stated in general) by
568: 971: 54:
Given a unit sphere, a "spherical triangle" on the surface of the sphere is defined by the
2717: 8: 2607: 365:
A variation on the law of cosines, the second spherical law of cosines, (also called the
287: 32: 2721: 2619: 359: 1648: 1335:
The first and second spherical laws of cosines can be rearranged to put the sides (
2687:
R. W. Sinnott, "Virtues of the Haversine", Sky and Telescope 68 (2), 159 (1984).
2394: 564: 349: 36: 2734: 1265: 55: 40: 1269: 1089:
from the center of the sphere to those corners of the triangle. We have
1086: 512: 74:
on the sphere (shown at right). If the lengths of these three sides are
2603: 1788:
Substituting these expressions into the spherical law of cosines nets:
538: 256:
are reinterpreted as the subtended angles). As a special case, for
46: 2657:
W. Gellert, S. Gottwald, M. Hellwich, H. Kästner, and H. Küstner,
2714:
Heavenly mathematics: The forgotten art of spherical trigonometry
237: 478:, respectively. It can be obtained from consideration of a 358:
is small. In this case, the alternative formulation of the
961:{\displaystyle (x,y,z)=(\sin b\cos C,\sin b\sin C,\cos b).} 2661:, 2nd ed., ch. 12 (Van Nostrand Reinhold: New York, 1989). 994:
is the dot product of the two Cartesian vectors, which is
445:{\displaystyle \cos C=-\cos A\cos B+\sin A\sin B\cos c\,} 211:{\displaystyle \cos c=\cos a\cos b+\sin a\sin b\cos C\,} 2448: 2118: 1796: 1657: 1634:{\displaystyle c^{2}\approx a^{2}+b^{2}-2ab\cos C\,.} 1569: 1369: 1000: 974: 873: 851: 777: 755: 690: 668: 599: 577: 547: 521: 377: 298: 146: 2701:. Szalay Könyvkiadó és Kereskedőház Kft. p. 83. 2440:
get small, so we can write this last expression as:
138:, then the (first) spherical law of cosines states: 2583: 2383: 2100: 1778: 1633: 1528: 1054: 986: 960: 859: 837: 763: 741: 676: 650: 585: 555: 529: 444: 348:, the necessity of inverting the cosine magnifies 332: 210: 2732: 1055:{\displaystyle \sin a\sin b\cos C+\cos a\cos b.} 466:are the angles of the corners opposite to sides 286:, and one obtains the spherical analogue of the 50:Spherical triangle solved by the law of cosines. 31:) is a theorem relating the sides and angles of 2711: 1538: 16:Mathematical relation in spherical triangles 2659:The VNR Concise Encyclopedia of Mathematics 1176:respectively and the angle between them is 567:(longitude of 0). With this rotation, the 342:If the law of cosines is used to solve for 2716:. Princeton University Press. p. 98. 742:{\displaystyle (r,\theta ,\phi )=(1,b,C).} 651:{\displaystyle (r,\theta ,\phi )=(1,a,0),} 1627: 838:{\displaystyle (x,y,z)=(\sin a,0,\cos a)} 441: 329: 220:Since this is a unit sphere, the lengths 207: 126:), and the angle of the corner opposite 45: 2733: 2696: 2664: 1363:) on opposite sides of the equations: 2653: 2651: 2649: 333:{\displaystyle \cos c=\cos a\cos b\,} 1547:spherical triangles, i.e. for small 2670:Romuald Ireneus 'Scibor-Marchocki, 1651:for the cosine and sine functions: 236:are simply equal to the angles (in 13: 2646: 845:and the Cartesian coordinates for 14: 2757: 1330: 2676:Elementary-Geometry Trigonometry 853: 757: 670: 579: 549: 523: 1643:To prove this, we will use the 1064: 2705: 2690: 2681: 1985: 1979: 952: 898: 892: 874: 832: 802: 796: 778: 749:The Cartesian coordinates for 733: 715: 709: 691: 642: 624: 618: 600: 490: 1: 2712:Van Brummelen, Glen (2012). 860:{\displaystyle \mathbf {w} } 764:{\displaystyle \mathbf {v} } 677:{\displaystyle \mathbf {w} } 586:{\displaystyle \mathbf {v} } 556:{\displaystyle \mathbf {v} } 530:{\displaystyle \mathbf {u} } 35:, analogous to the ordinary 7: 2699:Geometria és határterületei 2613: 10: 2762: 2593: 1539:Planar limit: small angles 2625:Hyperbolic law of cosines 1645:small-angle approximation 485: 2640: 58:connecting three points 2697:Reiman, István (1999). 480:spherical triangle dual 2741:Spherical trigonometry 2672:Spherical trigonometry 2635:Spherical law of sines 2585: 2385: 2110:or after simplifying: 2102: 1780: 1635: 1530: 1056: 988: 987:{\displaystyle \cos c} 962: 861: 839: 765: 743: 678: 652: 587: 557: 531: 446: 367:cosine rule for angles 334: 212: 51: 21:spherical trigonometry 2630:Solution of triangles 2586: 2386: 2103: 1781: 1636: 1531: 1274:Binet–Cauchy identity 1057: 989: 963: 862: 840: 766: 744: 679: 653: 588: 569:spherical coordinates 558: 532: 447: 335: 213: 49: 29:cosine rule for sides 2746:Theorems in geometry 2446: 2116: 1794: 1655: 1567: 1367: 998: 972: 871: 849: 775: 753: 688: 666: 597: 575: 563:is somewhere on the 545: 519: 375: 296: 144: 2722:2012hmfa.book.....V 2606:(9th century), and 288:Pythagorean theorem 33:spherical triangles 2581: 2381: 2098: 1776: 1774: 1647:obtained from the 1631: 1526: 1524: 1052: 984: 958: 857: 835: 761: 739: 674: 648: 583: 553: 527: 482:to the given one. 442: 330: 208: 52: 2620:Half-side formula 2409:are dominated by 1920: 1888: 1868: 1818: 1699: 1520: 1444: 360:law of haversines 27:(also called the 2753: 2726: 2725: 2709: 2703: 2702: 2694: 2688: 2685: 2679: 2678:web page (1997). 2668: 2662: 2655: 2610:(15th century). 2590: 2588: 2587: 2582: 2577: 2573: 2572: 2553: 2549: 2548: 2529: 2525: 2524: 2484: 2483: 2471: 2470: 2458: 2457: 2439: 2433: 2427: 2408: 2402: 2390: 2388: 2387: 2382: 2377: 2373: 2372: 2371: 2362: 2361: 2341: 2337: 2336: 2335: 2312: 2308: 2304: 2303: 2283: 2279: 2278: 2277: 2268: 2267: 2247: 2243: 2242: 2223: 2219: 2218: 2199: 2195: 2194: 2154: 2153: 2141: 2140: 2128: 2127: 2107: 2105: 2104: 2099: 2097: 2093: 2092: 2088: 2087: 2086: 2077: 2076: 2056: 2052: 2051: 2050: 2027: 2023: 2019: 2018: 1969: 1965: 1964: 1945: 1941: 1940: 1921: 1916: 1915: 1914: 1905: 1904: 1894: 1889: 1884: 1883: 1874: 1869: 1864: 1863: 1854: 1843: 1839: 1838: 1819: 1814: 1813: 1804: 1785: 1783: 1782: 1777: 1775: 1771: 1767: 1766: 1724: 1720: 1719: 1700: 1695: 1694: 1685: 1649:Maclaurin series 1640: 1638: 1637: 1632: 1605: 1604: 1592: 1591: 1579: 1578: 1562: 1556: 1535: 1533: 1532: 1527: 1525: 1521: 1519: 1499: 1467: 1445: 1443: 1423: 1391: 1362: 1348: 1326: 1259: 1181: 1175: 1168: 1161: 1151: 1141: 1127: 1113: 1099: 1084: 1078: 1061: 1059: 1058: 1053: 993: 991: 990: 985: 967: 965: 964: 959: 866: 864: 863: 858: 856: 844: 842: 841: 836: 770: 768: 767: 762: 760: 748: 746: 745: 740: 683: 681: 680: 675: 673: 661: 657: 655: 654: 649: 592: 590: 589: 584: 582: 562: 560: 559: 554: 552: 536: 534: 533: 528: 526: 510: 504: 477: 471: 465: 459: 451: 449: 448: 443: 357: 347: 339: 337: 336: 331: 285: 277: 276: 274: 273: 270: 267: 255: 249: 235: 229: 217: 215: 214: 209: 137: 131: 125: 119: 113: 107: 101: 95: 85: 79: 73: 67: 2761: 2760: 2756: 2755: 2754: 2752: 2751: 2750: 2731: 2730: 2729: 2710: 2706: 2695: 2691: 2686: 2682: 2669: 2665: 2656: 2647: 2643: 2616: 2602:(9th century), 2596: 2568: 2564: 2560: 2544: 2540: 2536: 2520: 2516: 2512: 2479: 2475: 2466: 2462: 2453: 2449: 2447: 2444: 2443: 2435: 2429: 2410: 2404: 2398: 2367: 2363: 2357: 2353: 2352: 2348: 2331: 2327: 2323: 2319: 2299: 2295: 2294: 2290: 2273: 2269: 2263: 2259: 2258: 2254: 2238: 2234: 2230: 2214: 2210: 2206: 2190: 2186: 2182: 2149: 2145: 2136: 2132: 2123: 2119: 2117: 2114: 2113: 2082: 2078: 2072: 2068: 2067: 2063: 2046: 2042: 2038: 2034: 2014: 2010: 2009: 2005: 1992: 1988: 1960: 1956: 1952: 1936: 1932: 1928: 1910: 1906: 1900: 1896: 1895: 1893: 1879: 1875: 1873: 1859: 1855: 1853: 1834: 1830: 1826: 1809: 1805: 1803: 1795: 1792: 1791: 1773: 1772: 1762: 1758: 1754: 1738: 1726: 1725: 1715: 1711: 1707: 1690: 1686: 1684: 1671: 1658: 1656: 1653: 1652: 1600: 1596: 1587: 1583: 1574: 1570: 1568: 1565: 1564: 1558: 1548: 1541: 1523: 1522: 1500: 1468: 1466: 1459: 1447: 1446: 1424: 1392: 1390: 1383: 1370: 1368: 1365: 1364: 1350: 1336: 1333: 1276: 1186: 1177: 1170: 1163: 1153: 1143: 1142:. The vectors 1129: 1115: 1101: 1090: 1080: 1070: 1067: 999: 996: 995: 973: 970: 969: 872: 869: 868: 852: 850: 847: 846: 776: 773: 772: 756: 754: 751: 750: 689: 686: 685: 669: 667: 664: 663: 659: 598: 595: 594: 578: 576: 573: 572: 548: 546: 543: 542: 522: 520: 517: 516: 506: 496: 493: 488: 473: 467: 461: 455: 376: 373: 372: 362:is preferable. 353: 350:rounding errors 343: 297: 294: 293: 279: 271: 268: 265: 264: 262: 257: 251: 241: 231: 221: 145: 142: 141: 133: 127: 121: 115: 109: 103: 97: 87: 81: 75: 69: 59: 17: 12: 11: 5: 2759: 2749: 2748: 2743: 2728: 2727: 2704: 2689: 2680: 2663: 2644: 2642: 2639: 2638: 2637: 2632: 2627: 2622: 2615: 2612: 2595: 2592: 2580: 2576: 2571: 2567: 2563: 2559: 2556: 2552: 2547: 2543: 2539: 2535: 2532: 2528: 2523: 2519: 2515: 2511: 2508: 2505: 2502: 2499: 2496: 2493: 2490: 2487: 2482: 2478: 2474: 2469: 2465: 2461: 2456: 2452: 2380: 2376: 2370: 2366: 2360: 2356: 2351: 2347: 2344: 2340: 2334: 2330: 2326: 2322: 2318: 2315: 2311: 2307: 2302: 2298: 2293: 2289: 2286: 2282: 2276: 2272: 2266: 2262: 2257: 2253: 2250: 2246: 2241: 2237: 2233: 2229: 2226: 2222: 2217: 2213: 2209: 2205: 2202: 2198: 2193: 2189: 2185: 2181: 2178: 2175: 2172: 2169: 2166: 2163: 2160: 2157: 2152: 2148: 2144: 2139: 2135: 2131: 2126: 2122: 2096: 2091: 2085: 2081: 2075: 2071: 2066: 2062: 2059: 2055: 2049: 2045: 2041: 2037: 2033: 2030: 2026: 2022: 2017: 2013: 2008: 2004: 2001: 1998: 1995: 1991: 1987: 1984: 1981: 1978: 1975: 1972: 1968: 1963: 1959: 1955: 1951: 1948: 1944: 1939: 1935: 1931: 1927: 1924: 1919: 1913: 1909: 1903: 1899: 1892: 1887: 1882: 1878: 1872: 1867: 1862: 1858: 1852: 1849: 1846: 1842: 1837: 1833: 1829: 1825: 1822: 1817: 1812: 1808: 1802: 1799: 1770: 1765: 1761: 1757: 1753: 1750: 1747: 1744: 1741: 1739: 1737: 1734: 1731: 1728: 1727: 1723: 1718: 1714: 1710: 1706: 1703: 1698: 1693: 1689: 1683: 1680: 1677: 1674: 1672: 1670: 1667: 1664: 1661: 1660: 1630: 1626: 1623: 1620: 1617: 1614: 1611: 1608: 1603: 1599: 1595: 1590: 1586: 1582: 1577: 1573: 1540: 1537: 1518: 1515: 1512: 1509: 1506: 1503: 1498: 1495: 1492: 1489: 1486: 1483: 1480: 1477: 1474: 1471: 1465: 1462: 1460: 1458: 1455: 1452: 1449: 1448: 1442: 1439: 1436: 1433: 1430: 1427: 1422: 1419: 1416: 1413: 1410: 1407: 1404: 1401: 1398: 1395: 1389: 1386: 1384: 1382: 1379: 1376: 1373: 1372: 1349:) and angles ( 1332: 1331:Rearrangements 1329: 1266:cross products 1262: 1261: 1066: 1063: 1051: 1048: 1045: 1042: 1039: 1036: 1033: 1030: 1027: 1024: 1021: 1018: 1015: 1012: 1009: 1006: 1003: 983: 980: 977: 957: 954: 951: 948: 945: 942: 939: 936: 933: 930: 927: 924: 921: 918: 915: 912: 909: 906: 903: 900: 897: 894: 891: 888: 885: 882: 879: 876: 855: 834: 831: 828: 825: 822: 819: 816: 813: 810: 807: 804: 801: 798: 795: 792: 789: 786: 783: 780: 759: 738: 735: 732: 729: 726: 723: 720: 717: 714: 711: 708: 705: 702: 699: 696: 693: 672: 647: 644: 641: 638: 635: 632: 629: 626: 623: 620: 617: 614: 611: 608: 605: 602: 581: 565:prime meridian 551: 525: 492: 489: 487: 484: 440: 437: 434: 431: 428: 425: 422: 419: 416: 413: 410: 407: 404: 401: 398: 395: 392: 389: 386: 383: 380: 328: 325: 322: 319: 316: 313: 310: 307: 304: 301: 206: 203: 200: 197: 194: 191: 188: 185: 182: 179: 176: 173: 170: 167: 164: 161: 158: 155: 152: 149: 37:law of cosines 25:law of cosines 15: 9: 6: 4: 3: 2: 2758: 2747: 2744: 2742: 2739: 2738: 2736: 2723: 2719: 2715: 2708: 2700: 2693: 2684: 2677: 2673: 2667: 2660: 2654: 2652: 2650: 2645: 2636: 2633: 2631: 2628: 2626: 2623: 2621: 2618: 2617: 2611: 2609: 2605: 2601: 2591: 2578: 2574: 2569: 2565: 2561: 2557: 2554: 2550: 2545: 2541: 2537: 2533: 2530: 2526: 2521: 2517: 2513: 2509: 2506: 2503: 2500: 2497: 2494: 2491: 2488: 2485: 2480: 2476: 2472: 2467: 2463: 2459: 2454: 2450: 2441: 2438: 2432: 2425: 2421: 2417: 2413: 2407: 2401: 2396: 2391: 2378: 2374: 2368: 2364: 2358: 2354: 2349: 2345: 2342: 2338: 2332: 2328: 2324: 2320: 2316: 2313: 2309: 2305: 2300: 2296: 2291: 2287: 2284: 2280: 2274: 2270: 2264: 2260: 2255: 2251: 2248: 2244: 2239: 2235: 2231: 2227: 2224: 2220: 2215: 2211: 2207: 2203: 2200: 2196: 2191: 2187: 2183: 2179: 2176: 2173: 2170: 2167: 2164: 2161: 2158: 2155: 2150: 2146: 2142: 2137: 2133: 2129: 2124: 2120: 2111: 2108: 2094: 2089: 2083: 2079: 2073: 2069: 2064: 2060: 2057: 2053: 2047: 2043: 2039: 2035: 2031: 2028: 2024: 2020: 2015: 2011: 2006: 2002: 1999: 1996: 1993: 1989: 1982: 1976: 1973: 1970: 1966: 1961: 1957: 1953: 1949: 1946: 1942: 1937: 1933: 1929: 1925: 1922: 1917: 1911: 1907: 1901: 1897: 1890: 1885: 1880: 1876: 1870: 1865: 1860: 1856: 1850: 1847: 1844: 1840: 1835: 1831: 1827: 1823: 1820: 1815: 1810: 1806: 1800: 1797: 1789: 1786: 1768: 1763: 1759: 1755: 1751: 1748: 1745: 1742: 1740: 1735: 1732: 1729: 1721: 1716: 1712: 1708: 1704: 1701: 1696: 1691: 1687: 1681: 1678: 1675: 1673: 1668: 1665: 1662: 1650: 1646: 1641: 1628: 1624: 1621: 1618: 1615: 1612: 1609: 1606: 1601: 1597: 1593: 1588: 1584: 1580: 1575: 1571: 1561: 1555: 1551: 1546: 1536: 1516: 1513: 1510: 1507: 1504: 1501: 1496: 1493: 1490: 1487: 1484: 1481: 1478: 1475: 1472: 1469: 1463: 1461: 1456: 1453: 1450: 1440: 1437: 1434: 1431: 1428: 1425: 1420: 1417: 1414: 1411: 1408: 1405: 1402: 1399: 1396: 1393: 1387: 1385: 1380: 1377: 1374: 1361: 1357: 1353: 1347: 1343: 1339: 1328: 1324: 1320: 1316: 1312: 1308: 1304: 1300: 1296: 1292: 1288: 1284: 1280: 1275: 1271: 1267: 1258: 1254: 1250: 1246: 1242: 1238: 1234: 1230: 1226: 1222: 1218: 1214: 1210: 1206: 1202: 1198: 1194: 1190: 1185: 1184: 1183: 1180: 1174: 1167: 1162:have lengths 1160: 1156: 1150: 1146: 1140: 1136: 1132: 1126: 1122: 1118: 1112: 1108: 1104: 1097: 1093: 1088: 1083: 1077: 1073: 1062: 1049: 1046: 1043: 1040: 1037: 1034: 1031: 1028: 1025: 1022: 1019: 1016: 1013: 1010: 1007: 1004: 1001: 981: 978: 975: 968:The value of 955: 949: 946: 943: 940: 937: 934: 931: 928: 925: 922: 919: 916: 913: 910: 907: 904: 901: 895: 889: 886: 883: 880: 877: 829: 826: 823: 820: 817: 814: 811: 808: 805: 799: 793: 790: 787: 784: 781: 736: 730: 727: 724: 721: 718: 712: 706: 703: 700: 697: 694: 645: 639: 636: 633: 630: 627: 621: 615: 612: 609: 606: 603: 570: 566: 540: 514: 509: 503: 499: 483: 481: 476: 470: 464: 458: 452: 438: 435: 432: 429: 426: 423: 420: 417: 414: 411: 408: 405: 402: 399: 396: 393: 390: 387: 384: 381: 378: 370: 368: 363: 361: 356: 351: 346: 340: 326: 323: 320: 317: 314: 311: 308: 305: 302: 299: 291: 289: 283: 260: 254: 248: 244: 239: 234: 228: 224: 218: 204: 201: 198: 195: 192: 189: 186: 183: 180: 177: 174: 171: 168: 165: 162: 159: 156: 153: 150: 147: 139: 136: 130: 124: 118: 112: 106: 100: 94: 90: 84: 78: 72: 66: 62: 57: 56:great circles 48: 44: 42: 38: 34: 30: 26: 22: 2713: 2707: 2698: 2692: 2683: 2675: 2666: 2658: 2600:al-Khwārizmī 2597: 2442: 2436: 2430: 2423: 2419: 2415: 2411: 2405: 2399: 2392: 2112: 2109: 1790: 1787: 1642: 1559: 1553: 1549: 1544: 1542: 1359: 1355: 1351: 1345: 1341: 1337: 1334: 1322: 1318: 1314: 1310: 1306: 1302: 1298: 1294: 1290: 1286: 1282: 1278: 1270:dot products 1263: 1256: 1252: 1248: 1244: 1240: 1236: 1232: 1228: 1224: 1220: 1216: 1212: 1208: 1204: 1200: 1196: 1192: 1188: 1178: 1172: 1165: 1158: 1154: 1148: 1144: 1138: 1134: 1130: 1124: 1120: 1116: 1110: 1106: 1102: 1095: 1091: 1087:unit vectors 1081: 1075: 1071: 1068: 1065:Second proof 513:unit vectors 507: 501: 497: 494: 474: 468: 462: 456: 453: 371: 366: 364: 354: 344: 341: 292: 281: 258: 252: 246: 242: 232: 226: 222: 219: 140: 134: 128: 122: 116: 110: 104: 98: 92: 88: 82: 76: 70: 64: 60: 53: 41:trigonometry 28: 24: 18: 1085:denote the 511:denote the 491:First proof 39:from plane 2735:Categories 2608:Nīlakaṇṭha 2604:al-Battānī 2397:terms for 1272:, and the 539:north pole 537:is at the 369:) states: 2501:⁡ 2486:− 2171:⁡ 2156:− 1977:⁡ 1871:− 1851:− 1801:− 1733:⁡ 1682:− 1666:⁡ 1622:⁡ 1607:− 1581:≈ 1514:⁡ 1505:⁡ 1494:⁡ 1485:⁡ 1473:⁡ 1454:⁡ 1438:⁡ 1429:⁡ 1418:⁡ 1409:⁡ 1403:− 1397:⁡ 1378:⁡ 1044:⁡ 1035:⁡ 1023:⁡ 1014:⁡ 1005:⁡ 979:⁡ 947:⁡ 935:⁡ 926:⁡ 914:⁡ 905:⁡ 827:⁡ 809:⁡ 707:ϕ 701:θ 616:ϕ 610:θ 436:⁡ 427:⁡ 418:⁡ 406:⁡ 397:⁡ 391:− 382:⁡ 324:⁡ 315:⁡ 303:⁡ 202:⁡ 193:⁡ 184:⁡ 172:⁡ 163:⁡ 151:⁡ 2614:See also 1247:) = cos 2718:Bibcode 2594:History 278:, then 275:⁠ 263:⁠ 238:radians 108:), and 1557:, and 1264:using 1251:− cos 1137:= cos 1128:, and 1123:= cos 1109:= cos 1079:, and 658:where 505:, and 486:Proofs 454:where 230:, and 114:(from 96:(from 80:(from 68:, and 23:, the 2641:Notes 2395:big O 1545:small 1309:) − ( 1293:) = ( 1285:) · ( 1231:) − ( 1215:) = ( 1207:) · ( 1182:, so 352:when 2434:and 2418:) + 2403:and 2393:The 1543:For 1255:cos 1195:cos 1191:sin 1187:sin 1171:sin 1169:and 1164:sin 1152:and 1069:Let 867:are 771:are 684:are 593:are 571:for 541:and 495:Let 472:and 460:and 280:cos 250:and 2498:cos 2428:as 2168:cos 1974:cos 1730:sin 1663:cos 1619:cos 1511:sin 1502:sin 1491:cos 1482:cos 1470:cos 1451:cos 1435:sin 1426:sin 1415:cos 1406:cos 1394:cos 1375:cos 1199:= ( 1098:= 1 1041:cos 1032:cos 1020:cos 1011:sin 1002:sin 976:cos 944:cos 932:sin 923:sin 911:cos 902:sin 824:cos 806:sin 433:cos 424:sin 415:sin 403:cos 394:cos 379:cos 321:cos 312:cos 300:cos 284:= 0 199:cos 190:sin 181:sin 169:cos 160:cos 148:cos 132:is 120:to 102:to 91:), 86:to 19:In 2737:: 2674:, 2648:^ 1552:, 1358:, 1354:, 1344:, 1340:, 1327:. 1321:· 1317:)( 1313:· 1305:· 1301:)( 1297:· 1289:× 1281:× 1268:, 1243:· 1239:)( 1235:· 1227:· 1223:)( 1219:· 1211:× 1203:× 1157:× 1147:× 1133:· 1119:· 1114:, 1105:· 1100:, 1094:· 1074:, 500:, 290:: 261:= 245:, 225:, 63:, 43:. 2724:. 2720:: 2579:. 2575:) 2570:4 2566:c 2562:( 2558:O 2555:+ 2551:) 2546:4 2542:b 2538:( 2534:O 2531:+ 2527:) 2522:4 2518:a 2514:( 2510:O 2507:+ 2504:C 2495:b 2492:a 2489:2 2481:2 2477:b 2473:+ 2468:2 2464:a 2460:= 2455:2 2451:c 2437:b 2431:a 2426:) 2424:b 2422:( 2420:O 2416:a 2414:( 2412:O 2406:b 2400:a 2379:. 2375:) 2369:3 2365:b 2359:3 2355:a 2350:( 2346:O 2343:+ 2339:) 2333:3 2329:b 2325:a 2321:( 2317:O 2314:+ 2310:) 2306:b 2301:3 2297:a 2292:( 2288:O 2285:+ 2281:) 2275:2 2271:b 2265:2 2261:a 2256:( 2252:O 2249:+ 2245:) 2240:4 2236:b 2232:( 2228:O 2225:+ 2221:) 2216:4 2212:a 2208:( 2204:O 2201:+ 2197:) 2192:4 2188:c 2184:( 2180:O 2177:+ 2174:C 2165:b 2162:a 2159:2 2151:2 2147:b 2143:+ 2138:2 2134:a 2130:= 2125:2 2121:c 2095:) 2090:) 2084:3 2080:b 2074:3 2070:a 2065:( 2061:O 2058:+ 2054:) 2048:3 2044:b 2040:a 2036:( 2032:O 2029:+ 2025:) 2021:b 2016:3 2012:a 2007:( 2003:O 2000:+ 1997:b 1994:a 1990:( 1986:) 1983:C 1980:( 1971:+ 1967:) 1962:4 1958:b 1954:( 1950:O 1947:+ 1943:) 1938:4 1934:a 1930:( 1926:O 1923:+ 1918:4 1912:2 1908:b 1902:2 1898:a 1891:+ 1886:2 1881:2 1877:b 1866:2 1861:2 1857:a 1848:1 1845:= 1841:) 1836:4 1832:c 1828:( 1824:O 1821:+ 1816:2 1811:2 1807:c 1798:1 1769:) 1764:3 1760:a 1756:( 1752:O 1749:+ 1746:a 1743:= 1736:a 1722:) 1717:4 1713:a 1709:( 1705:O 1702:+ 1697:2 1692:2 1688:a 1679:1 1676:= 1669:a 1629:. 1625:C 1616:b 1613:a 1610:2 1602:2 1598:b 1594:+ 1589:2 1585:a 1576:2 1572:c 1560:c 1554:b 1550:a 1517:B 1508:A 1497:B 1488:A 1479:+ 1476:C 1464:= 1457:c 1441:b 1432:a 1421:b 1412:a 1400:c 1388:= 1381:C 1360:C 1356:B 1352:A 1346:c 1342:b 1338:a 1325:) 1323:r 1319:q 1315:s 1311:p 1307:s 1303:q 1299:r 1295:p 1291:s 1287:r 1283:q 1279:p 1277:( 1260:, 1257:b 1253:a 1249:c 1245:w 1241:u 1237:v 1233:u 1229:w 1225:v 1221:u 1217:u 1213:w 1209:u 1205:v 1201:u 1197:C 1193:b 1189:a 1179:C 1173:b 1166:a 1159:w 1155:u 1149:v 1145:u 1139:b 1135:w 1131:u 1125:a 1121:v 1117:u 1111:c 1107:w 1103:v 1096:u 1092:u 1082:w 1076:v 1072:u 1050:. 1047:b 1038:a 1029:+ 1026:C 1017:b 1008:a 982:c 956:. 953:) 950:b 941:, 938:C 929:b 920:, 917:C 908:b 899:( 896:= 893:) 890:z 887:, 884:y 881:, 878:x 875:( 854:w 833:) 830:a 821:, 818:0 815:, 812:a 803:( 800:= 797:) 794:z 791:, 788:y 785:, 782:x 779:( 758:v 737:. 734:) 731:C 728:, 725:b 722:, 719:1 716:( 713:= 710:) 704:, 698:, 695:r 692:( 671:w 660:θ 646:, 643:) 640:0 637:, 634:a 631:, 628:1 625:( 622:= 619:) 613:, 607:, 604:r 601:( 580:v 550:v 524:u 508:w 502:v 498:u 475:b 469:a 463:B 457:A 439:c 430:B 421:A 412:+ 409:B 400:A 388:= 385:C 355:c 345:c 327:b 318:a 309:= 306:c 282:C 272:2 269:/ 266:π 259:C 253:c 247:b 243:a 233:c 227:b 223:a 205:C 196:b 187:a 178:+ 175:b 166:a 157:= 154:c 135:C 129:c 123:w 117:v 111:c 105:w 99:u 93:b 89:v 83:u 77:a 71:w 65:v 61:u

Index

spherical trigonometry
spherical triangles
law of cosines
trigonometry

great circles
radians
Pythagorean theorem
rounding errors
law of haversines
spherical triangle dual
unit vectors
north pole
prime meridian
spherical coordinates
unit vectors
cross products
dot products
Binet–Cauchy identity
small-angle approximation
Maclaurin series
big O
al-Khwārizmī
al-Battānī
Nīlakaṇṭha
Half-side formula
Hyperbolic law of cosines
Solution of triangles
Spherical law of sines

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