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Pascal's theorem

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If exactly one pair of opposite sides of the hexagon are parallel, then the conclusion of the theorem is that the "Pascal line" determined by the two points of intersection is parallel to the parallel sides of the hexagon. If two pairs of opposite sides are parallel, then all three pairs of opposite
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that given any 8 points in general position, there is a unique ninth point such that all cubics through the first 8 also pass through the ninth point. In particular, if 2 general cubics intersect in 8 points then any other cubic through the same 8 points meets the ninth point of intersection of the
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There exist 5-point, 4-point and 3-point degenerate cases of Pascal's theorem. In a degenerate case, two previously connected points of the figure will formally coincide and the connecting line becomes the tangent at the coalesced point. See the degenerate cases given in the added scheme and the
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It is sufficient to prove the theorem when the conic is a circle, because any (non-degenerate) conic can be reduced to a circle by a projective transformation. This was realised by Pascal, whose first lemma states the theorem for a circle. His second lemma states that what is true in one plane
1201:{\displaystyle {\frac {\overline {GB}}{\overline {GA}}}\times {\frac {\overline {HA}}{\overline {HF}}}\times {\frac {\overline {KF}}{\overline {KE}}}\times {\frac {\overline {GE}}{\overline {GD}}}\times {\frac {\overline {HD}}{\overline {HC}}}\times {\frac {\overline {KC}}{\overline {KB}}}=1.} 257:
are collinear in four points; the tangents being degenerate 'sides', taken at two possible positions on the 'hexagon' and the corresponding Pascal line sharing either degenerate intersection. This can be proven independently using a property of
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since any two lines meet and no exceptions need to be made for parallel lines. However, the theorem remains valid in the Euclidean plane, with the correct interpretation of what happens when some opposite sides of the hexagon are parallel.
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Thus the group operation is associative. On the other hand, Pascal's theorem follows from the above associativity formula, and thus from the associativity of the group operation of elliptic curves by way of continuity.
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If six unordered points are given on a conic section, they can be connected into a hexagon in 60 different ways, resulting in 60 different instances of Pascal's theorem and 60 different Pascal lines. This
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proved in 1849, these 60 lines can be associated with 60 points in such a way that each point is on three lines and each line contains three points. The 60 points formed in this way are now known as the
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remains true upon projection to another plane. Degenerate conics follow by continuity (the theorem is true for non-degenerate conics, and thus holds in the limit of degenerate conic).
583:, where one of the points in the two tetrads overlap, hence meaning that other lines connecting the other three pairs must coincide to preserve cross ratio. Therefore, 707:
is also used to prove that the group operation on cubic elliptic curves is associative. The same group operation can be applied on a conic if we choose a point
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a cubic and a conic have at most 3 × 2 = 6 points in common, unless they have a common component. So the cubic
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first two cubics. Pascal's theorem follows by taking the 8 points as the 6 points on the hexagon and two of the points (say,
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Again given the hexagon on a conic of Pascal's theorem with the above notation for points (in the first figure), we have
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in the figure). The first two cubics are two sets of 3 lines through the 6 points on the hexagon (for instance, the set
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which consist of a Steiner point and three Kirkman points. The Steiner points also lie, four at a time, on 15
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sides form pairs of parallel lines and there is no Pascal line in the Euclidean plane (in this case, the
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sides is inscribed in a conic section, and opposite pairs of sides are extended until they meet in
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is the union of the conic and a line. It is now easy to check that this line is the Pascal line.
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will correspond to the isogonal conjugate if we overlap the similar triangles. This means that
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Six is the minimum number of points on a conic about which special statements can be made, as
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A short elementary computational proof in the case of the real projective plane was found by
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Pascal's original note has no proof, but there are various modern proofs of the theorem.
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in a note written in 1639 when he was 16 years old and published the following year as a
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Theorem on the collinearity of three points generated from a hexagon inscribed on a conic
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Planar Circle Geometries, an Introduction to Moebius-, Laguerre- and Minkowski Planes
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in the figure) on the would-be Pascal line, and the ninth point as the third point (
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A short proof can be constructed using cross-ratio preservation. Projecting tetrad
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A short elementary proof of Pascal's theorem in the case of a circle was found by
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A degenerate case of Pascal's theorem (four points) is interesting; given points
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of those points lie on a common line, the last point will be on that line, too.
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construction of the conic defined by five points, by varying the sixth point.
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There also exists a simple proof for Pascal's theorem for a circle using the
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has a component in common with the conic which must be the conic itself, so
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if necessary) meet at three points which lie on a straight line, called the
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Mills, Stella (March 1984), "Note on the Braikenridge–Maclaurin Theorem",
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van Yzeren, Jan (1993), "A simple proof of Pascal's hexagon theorem",
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A very simple proof of Pascal's hexagon theorem and some applications
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of the extended Euclidean plane is the Pascal line of the hexagon).
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inscribed in ellipse. Opposite sides of hexagon have the same color.
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add up to the second intersection point of the conic with line
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is the cubic polynomial vanishing on the three lines through
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is obtained by first finding the intersection point of line
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cannot lie on the conic by genericity, and hence it lies on
1368:"A Property of Pascal's Hexagon Pascal May Have Overlooked" 633:
The intersections of the extended opposite sides of simple
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by J. Chris Fisher and Norma Fuller (University of Regina)
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The Penguin Dictionary of Curious and Interesting Geometry
361:. The Pascal lines also pass, three at a time, through 20 1423:; Ryba, Alex (2012), "The Pascal Mysticum Demystified", 779:
is the second intersection point of the conic with line
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The most natural setting for Pascal's theorem is in a
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Another proof for Pascal's theorem for a circle uses
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Interactive demo of Pascal's theorem (Java required)
1640:(10), Mathematical Association of America: 930–931, 1834: 1803: 1758: 1319:, p. 67 with a reference to Veblen and Young, 1600: 1200: 872: 1701:The Complete Pascal Figure Graphically Presented 1491:Notes and Records of the Royal Society of London 910:is the cubic vanishing on the other three lines 280:, named for 18th-century British mathematicians 1304: 1715:How to Project Spherical Conics into the Plane 1736: 647:Pascal's theorem has a short proof using the 602:, the geometer who discovered the celebrated 144:of two lines with three points on each line. 8: 1711:(PDF; 891 kB), Uni Darmstadt, S. 29–35. 397: 307:in 1847, as follows: suppose a polygon with 193:titled "Essay pour les coniques. Par B. P." 1391:Bulletin of the London Mathematical Society 1743: 1729: 1721: 1525:Modenov, P.S.; Parkhomenko, A.S. (2001) , 1477:, San Francisco, Calif.: Holden–Day Inc., 1332: 643:(right) lie on the Pascal line MNP (left). 404: 393: 196:Pascal's theorem is a special case of the 1162: 1129: 1096: 1063: 1030: 997: 995: 873:{\displaystyle (A+B)+C=D+C=Q=A+F=A+(B+C)} 793: 410:We can infer the proof from existence of 1388:(1981), "T. P. Kirkman, mathematician", 1215: 49: 29: 1268: 213:, the intersection of alternate sides, 1280: 1276: 1274: 1272: 1354: 1343: 1316: 1284: 289: 7: 1892: 136:This theorem is a generalization of 1466:Mathematical Association of America 294:Braikenridge–Maclaurin construction 110:, then the three pairs of opposite 1717:by Yoichi Maeda (Tokai University) 1473:Guggenheimer, Heinrich W. (1967), 122:of the hexagon. It is named after 25: 1633:The American Mathematical Monthly 1497:(2), The Royal Society: 235–240, 1212:Degenerations of Pascal's theorem 961:in common with the conic. But by 140:, which is the special case of a 129:The theorem is also valid in the 1891: 1882: 1881: 688:. Here the "ninth intersection" 1928:Theorems in projective geometry 1692:60 Pascal Lines (Java required) 1220:Pascal's theorem: degenerations 303:The theorem was generalized by 1426:The Mathematical Intelligencer 983:A property of Pascal's hexagon 867: 855: 807: 795: 278:Braikenridge–Maclaurin theorem 1: 1585:Stefanovic, Nedeljko (2010), 1475:Plane geometry and its groups 955:is a cubic that has 7 points 271:five points determine a conic 1594:, Indian Academy of Sciences 1568:A Source Book in Mathematics 1565:Smith, David Eugene (1959), 1186: 1173: 1153: 1140: 1120: 1107: 1087: 1074: 1054: 1041: 1021: 1008: 888:Proof using BĂ©zout's theorem 556:. This therefore means that 456:are collinear for concyclic 414:too. If we are to show that 75:hexagrammum mysticum theorem 1621:Young, John Wesley (1930), 1532:Encyclopedia of Mathematics 1954: 345:of 60 lines is called the 138:Pappus's (hexagon) theorem 1877: 1607:, London: Penguin Books, 1545:"Essay pour les coniques" 1439:10.1007/s00283-012-9301-4 1323:, vol. I, p. 138, Ex. 19. 719:in the plane. The sum of 396:, based on the proof in ( 40:of self-crossing hexagon 1938:Euclidean plane geometry 922:on the conic and choose 713:on the conic and a line 705:Cayley–Bacharach theorem 649:Cayley–Bacharach theorem 625:Proof using cubic curves 532:, and projecting tetrad 198:Cayley–Bacharach theorem 173:Pascal's theorem is the 1933:Theorems about polygons 1543:Pascal, Blaise (1640). 1211: 982: 916:. Pick a generic point 887: 305:August Ferdinand Möbius 185:. It was formulated by 1503:10.1098/rsnr.1984.0014 1333:Conway & Ryba 2012 1221: 1202: 874: 644: 476:are similar, and that 61: 54:Self-crossing hexagon 47: 1599:Wells, David (1991), 1219: 1203: 875: 632: 53: 33: 1812:Lettres provinciales 1404:10.1112/blms/13.2.97 1297:H. S. M. Coxeter 994: 792: 347:Hexagrammum Mysticum 335:Hexagrammum Mysticum 282:William Braikenridge 276:The converse is the 1775:Pascal's calculator 1623:Projective Geometry 1571:, New York: Dover, 1458:Greitzer, Samuel L. 1321:Projective Geometry 1252:Brianchon's theorem 1247:Desargues's theorem 958:A, B, C, D, E, F, P 550:, we obtain tetrad 526:, we obtain tetrad 462:, then notice that 183:Brianchon's theorem 72:(also known as the 66:projective geometry 1464:, Washington, DC: 1462:Geometry Revisited 1301:Samuel L. Greitzer 1257:Unicursal hexagram 1222: 1198: 928:so that the cubic 870: 645: 608:Desargues' theorem 412:isogonal conjugate 148:Euclidean variants 102:in an appropriate 62: 48: 1905: 1904: 1866:Marguerite PĂ©rier 1850:Jacqueline Pascal 1816:(1656–1657) 1790:Pascal's triangle 1454:Coxeter, H. S. M. 1227:circle geometries 1225:external link on 1190: 1189: 1176: 1157: 1156: 1143: 1124: 1123: 1110: 1091: 1090: 1077: 1058: 1057: 1044: 1025: 1024: 1011: 594:Menelaus' theorem 405:Stefanovic (2010) 398:Guggenheimer 1967 394:van Yzeren (1993) 266:, are collinear. 264:Gergonne triangle 90:(which may be an 16:(Redirected from 1945: 1895: 1894: 1885: 1884: 1870: 1862: 1854: 1846: 1827: 1817: 1785:Pascal's theorem 1745: 1738: 1731: 1722: 1672: 1626: 1617: 1606: 1595: 1593: 1581: 1559: 1557: 1555: 1549: 1539: 1527:"Pascal theorem" 1521: 1485: 1469: 1449: 1414: 1372: 1371: 1364: 1358: 1352: 1346: 1341: 1335: 1330: 1324: 1314: 1308: 1294: 1288: 1278: 1207: 1205: 1204: 1199: 1191: 1185: 1177: 1172: 1164: 1163: 1158: 1152: 1144: 1139: 1131: 1130: 1125: 1119: 1111: 1106: 1098: 1097: 1092: 1086: 1078: 1073: 1065: 1064: 1059: 1053: 1045: 1040: 1032: 1031: 1026: 1020: 1012: 1007: 999: 998: 978: 971: 963:BĂ©zout's theorem 960: 954: 947: 941: 927: 921: 915: 909: 903: 897: 879: 877: 876: 871: 784: 778: 772: 766: 760: 754: 748: 742: 736: 730: 724: 718: 712: 699: 693: 687: 681: 675: 669: 663: 657: 642: 604:Dandelin spheres 588: 582: 555: 549: 543: 537: 531: 525: 519: 513: 504: 498: 487: 481: 475: 468: 461: 455: 441: 427: 329: 323:points. Then if 322: 314: 256: 244: 232: 222: 212: 208: 175:polar reciprocal 163:line at infinity 154:projective plane 142:degenerate conic 114:of the hexagon ( 70:Pascal's theorem 59: 45: 39: 21: 1953: 1952: 1948: 1947: 1946: 1944: 1943: 1942: 1908: 1907: 1906: 1901: 1873: 1868: 1860: 1858:Gilberte PĂ©rier 1852: 1844: 1830: 1825: 1815: 1799: 1768: 1754: 1749: 1679: 1646:10.2307/2324214 1629: 1620: 1615: 1598: 1591: 1584: 1579: 1564: 1553: 1551: 1547: 1542: 1524: 1488: 1472: 1452: 1419: 1384: 1381: 1376: 1375: 1366: 1365: 1361: 1353: 1349: 1342: 1338: 1331: 1327: 1315: 1311: 1295: 1291: 1279: 1270: 1265: 1243: 1214: 1178: 1165: 1145: 1132: 1112: 1099: 1079: 1066: 1046: 1033: 1013: 1000: 992: 991: 985: 973: 966: 956: 949: 943: 929: 923: 917: 911: 905: 899: 893: 890: 790: 789: 780: 774: 768: 762: 756: 750: 744: 738: 732: 726: 720: 714: 708: 695: 689: 683: 677: 671: 665: 659: 653: 638: 627: 589:are collinear. 584: 557: 551: 545: 539: 533: 527: 521: 515: 509: 500: 499:, hence making 489: 483: 477: 470: 463: 457: 443: 429: 415: 383: 365:. There are 20 338: 324: 316: 308: 286:Colin Maclaurin 246: 234: 224: 214: 210: 204: 179:projective dual 171: 169:Related results 150: 131:Euclidean plane 55: 41: 35: 28: 23: 22: 15: 12: 11: 5: 1951: 1949: 1941: 1940: 1935: 1930: 1925: 1923:Conic sections 1920: 1910: 1909: 1903: 1902: 1900: 1899: 1889: 1878: 1875: 1874: 1872: 1871: 1863: 1855: 1847: 1842:Étienne Pascal 1838: 1836: 1832: 1831: 1829: 1828: 1818: 1807: 1805: 1801: 1800: 1798: 1797: 1795:Pascal's wager 1792: 1787: 1782: 1777: 1771: 1769: 1767: 1766: 1763: 1759: 1756: 1755: 1750: 1748: 1747: 1740: 1733: 1725: 1719: 1718: 1712: 1704: 1698: 1689: 1678: 1677:External links 1675: 1674: 1673: 1627: 1618: 1613: 1596: 1582: 1577: 1561: 1560: 1540: 1522: 1486: 1470: 1450: 1416: 1415: 1380: 1377: 1374: 1373: 1359: 1347: 1336: 1325: 1309: 1289: 1283:, translation 1267: 1266: 1264: 1261: 1260: 1259: 1254: 1249: 1242: 1239: 1213: 1210: 1209: 1208: 1197: 1194: 1188: 1184: 1181: 1175: 1171: 1168: 1161: 1155: 1151: 1148: 1142: 1138: 1135: 1128: 1122: 1118: 1115: 1109: 1105: 1102: 1095: 1089: 1085: 1082: 1076: 1072: 1069: 1062: 1056: 1052: 1049: 1043: 1039: 1036: 1029: 1023: 1019: 1016: 1010: 1006: 1003: 984: 981: 889: 886: 881: 880: 869: 866: 863: 860: 857: 854: 851: 848: 845: 842: 839: 836: 833: 830: 827: 824: 821: 818: 815: 812: 809: 806: 803: 800: 797: 676:, and the set 626: 623: 382: 379: 363:Steiner points 359:Kirkman points 354:Thomas Kirkman 337: 332: 170: 167: 149: 146: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 1950: 1939: 1936: 1934: 1931: 1929: 1926: 1924: 1921: 1919: 1918:Blaise Pascal 1916: 1915: 1913: 1898: 1890: 1888: 1880: 1879: 1876: 1867: 1864: 1859: 1856: 1851: 1848: 1843: 1840: 1839: 1837: 1833: 1824: 1823: 1819: 1814: 1813: 1809: 1808: 1806: 1802: 1796: 1793: 1791: 1788: 1786: 1783: 1781: 1778: 1776: 1773: 1772: 1770: 1764: 1761: 1760: 1757: 1753: 1752:Blaise Pascal 1746: 1741: 1739: 1734: 1732: 1727: 1726: 1723: 1716: 1713: 1710: 1709: 1705: 1702: 1699: 1697: 1693: 1690: 1688: 1684: 1681: 1680: 1676: 1671: 1667: 1663: 1659: 1655: 1651: 1647: 1643: 1639: 1635: 1634: 1628: 1624: 1619: 1616: 1614:0-14-011813-6 1610: 1605: 1604: 1597: 1590: 1589: 1583: 1580: 1578:0-486-64690-4 1574: 1570: 1569: 1563: 1562: 1546: 1541: 1538: 1534: 1533: 1528: 1523: 1520: 1516: 1512: 1508: 1504: 1500: 1496: 1492: 1487: 1484: 1480: 1476: 1471: 1467: 1463: 1459: 1455: 1451: 1448: 1444: 1440: 1436: 1432: 1428: 1427: 1422: 1418: 1417: 1413: 1409: 1405: 1401: 1398:(2): 97–120, 1397: 1393: 1392: 1387: 1383: 1382: 1378: 1370:. 2014-02-03. 1369: 1363: 1360: 1357:, p. 172 1356: 1351: 1348: 1345: 1340: 1337: 1334: 1329: 1326: 1322: 1318: 1313: 1310: 1306: 1302: 1299: and 1298: 1293: 1290: 1287:, p. 326 1286: 1282: 1277: 1275: 1273: 1269: 1262: 1258: 1255: 1253: 1250: 1248: 1245: 1244: 1240: 1238: 1236: 1232: 1228: 1218: 1195: 1192: 1182: 1179: 1169: 1166: 1159: 1149: 1146: 1136: 1133: 1126: 1116: 1113: 1103: 1100: 1093: 1083: 1080: 1070: 1067: 1060: 1050: 1047: 1037: 1034: 1027: 1017: 1014: 1004: 1001: 990: 989: 988: 980: 976: 969: 964: 959: 952: 946: 940: 936: 932: 926: 920: 914: 908: 902: 896: 885: 864: 861: 858: 852: 849: 846: 843: 840: 837: 834: 831: 828: 825: 822: 819: 816: 813: 810: 804: 801: 798: 788: 787: 786: 783: 777: 771: 765: 759: 753: 747: 741: 735: 729: 723: 717: 711: 706: 701: 698: 692: 686: 680: 674: 668: 662: 656: 650: 641: 636: 631: 624: 622: 620: 616: 611: 609: 605: 601: 597: 595: 590: 587: 580: 576: 572: 568: 564: 560: 554: 548: 542: 536: 530: 524: 518: 512: 506: 503: 497: 493: 486: 480: 474: 467: 460: 454: 450: 446: 440: 436: 432: 426: 422: 418: 413: 408: 406: 401: 399: 395: 390: 386: 380: 378: 376: 375:Salmon points 372: 371:PlĂŒcker lines 368: 364: 360: 355: 350: 348: 344: 343:configuration 336: 333: 331: 328: 320: 312: 306: 301: 299: 296:, which is a 295: 291: 287: 283: 279: 274: 272: 267: 265: 261: 254: 250: 242: 238: 231: 227: 221: 217: 207: 201: 199: 194: 192: 188: 187:Blaise Pascal 184: 180: 176: 168: 166: 164: 158: 155: 147: 145: 143: 139: 134: 132: 127: 125: 124:Blaise Pascal 121: 117: 113: 109: 105: 101: 97: 93: 89: 85: 82:for mystical 81: 77: 76: 71: 67: 58: 52: 44: 38: 32: 19: 1820: 1810: 1784: 1780:Pascal's law 1707: 1696:cut-the-knot 1687:cut-the-knot 1637: 1631: 1622: 1602: 1587: 1567: 1552:. Retrieved 1530: 1494: 1490: 1474: 1468:, p. 76 1461: 1430: 1424: 1421:Conway, John 1395: 1389: 1386:Biggs, N. L. 1362: 1350: 1339: 1328: 1320: 1312: 1292: 1226: 1223: 986: 974: 967: 957: 950: 944: 942:vanishes on 938: 934: 930: 924: 918: 912: 906: 900: 894: 891: 882: 781: 775: 769: 763: 757: 751: 745: 739: 733: 727: 721: 715: 709: 702: 696: 690: 684: 678: 672: 666: 660: 654: 646: 639: 615:law of sines 612: 598: 596:repeatedly. 591: 585: 578: 574: 570: 566: 562: 558: 552: 546: 540: 534: 528: 522: 516: 510: 507: 501: 495: 491: 484: 478: 472: 465: 458: 452: 448: 444: 438: 434: 430: 424: 420: 416: 409: 402: 391: 387: 384: 374: 370: 367:Cayley lines 366: 362: 358: 351: 346: 339: 334: 326: 318: 310: 302: 275: 268: 252: 248: 240: 236: 229: 225: 219: 215: 205: 202: 195: 172: 159: 151: 135: 128: 119: 104:affine plane 74: 73: 69: 63: 56: 42: 36: 34:Pascal line 18:PlĂŒcker Line 1762:Innovations 1548:(facsimile) 1281:Pascal 1640 767:, which is 743:, which is 505:collinear. 209:on a conic 120:Pascal line 1912:Categories 1433:(3): 4–8, 1379:References 1355:Wells 1991 1344:Biggs 1981 1317:Young 1930 1285:Smith 1959 1235:hyperbolas 913:BC, DE, FA 901:AB, CD, EF 773:. Thus if 679:BC, DE, FA 673:AB, CD, EF 619:similarity 544:onto line 520:onto line 290:Mills 1984 260:pole-polar 1654:0002-9890 1537:EMS Press 1519:144663075 1447:122915551 1231:parabolas 1187:¯ 1174:¯ 1160:× 1154:¯ 1141:¯ 1127:× 1121:¯ 1108:¯ 1094:× 1088:¯ 1075:¯ 1061:× 1055:¯ 1042:¯ 1028:× 1022:¯ 1009:¯ 298:synthetic 191:broadside 100:hyperbola 1887:Category 1861:(sister) 1853:(sister) 1845:(father) 1460:(1967), 1241:See also 892:Suppose 637:hexagon 600:Dandelin 116:extended 96:parabola 84:hexagram 1897:Commons 1869:(niece) 1822:PensĂ©es 1670:1252929 1662:2324214 1554:21 June 1483:0213943 1412:0608093 1303: ( 948:. Then 785:, then 749:. Next 108:hexagon 92:ellipse 1835:Family 1826:(1669) 1765:Career 1668:  1660:  1652:  1611:  1575:  1517:  1511:531819 1509:  1481:  1445:  1410:  640:ABCDEF 635:cyclic 459:ABCDEF 381:Proofs 57:ABCDEF 43:ABCDEF 1804:Works 1658:JSTOR 1592:(PDF) 1515:S2CID 1507:JSTOR 1443:S2CID 1263:Notes 737:with 538:from 514:from 112:sides 88:conic 80:Latin 1650:ISSN 1609:ISBN 1573:ISBN 1556:2013 1305:1967 1233:and 904:and 755:and 725:and 703:The 658:and 617:and 569:) = 553:QBCY 535:ABCE 529:ABPX 511:ABCE 482:and 469:and 284:and 245:and 206:ABCD 177:and 1694:at 1685:at 1642:doi 1638:100 1499:doi 1435:doi 1400:doi 977:= 0 970:= 0 953:= 0 586:XYZ 502:XYZ 496:CYZ 494:= ∠ 492:CYX 473:CYF 466:EYB 352:As 321:+ 1 313:+ 2 181:of 98:or 64:In 37:GHK 1914:: 1666:MR 1664:, 1656:, 1648:, 1636:, 1535:, 1529:, 1513:, 1505:, 1495:38 1493:, 1479:MR 1456:; 1441:, 1431:34 1429:, 1408:MR 1406:, 1396:13 1394:, 1271:^ 1237:. 1196:1. 939:λg 937:+ 933:= 782:EN 764:EM 740:MP 734:AB 716:MP 700:. 697:MN 685:MN 621:. 579:CY 577:; 575:QB 567:PX 565:; 563:AB 547:BC 523:AB 453:FA 451:∩ 449:CD 447:= 442:, 439:EF 437:∩ 435:BC 433:= 428:, 425:DE 423:∩ 421:AB 419:= 407:. 377:. 349:. 273:. 251:, 239:, 230:DA 228:∩ 226:BC 223:, 220:CD 218:∩ 216:AB 200:. 126:. 94:, 78:, 68:, 1744:e 1737:t 1730:v 1644:: 1558:. 1501:: 1437:: 1402:: 1307:) 1193:= 1183:B 1180:K 1170:C 1167:K 1150:C 1147:H 1137:D 1134:H 1117:D 1114:G 1104:E 1101:G 1084:E 1081:K 1071:F 1068:K 1051:F 1048:H 1038:A 1035:H 1018:A 1015:G 1005:B 1002:G 975:h 968:h 951:h 945:P 935:f 931:h 925:λ 919:P 907:g 895:f 868:) 865:C 862:+ 859:B 856:( 853:+ 850:A 847:= 844:F 841:+ 838:A 835:= 832:Q 829:= 826:C 823:+ 820:D 817:= 814:C 811:+ 808:) 805:B 802:+ 799:A 796:( 776:Q 770:D 758:B 752:A 746:M 728:B 722:A 710:E 691:P 667:P 661:N 655:M 581:) 573:( 571:R 561:( 559:R 541:F 517:D 490:∠ 485:Z 479:X 471:△ 464:△ 445:Z 431:Y 417:X 327:n 325:2 319:n 317:2 311:n 309:4 288:( 255:) 253:D 249:B 247:( 243:) 241:C 237:A 235:( 211:Γ 20:)

Index

PlĂŒcker Line


projective geometry
Latin
hexagram
conic
ellipse
parabola
hyperbola
affine plane
hexagon
sides
extended
Blaise Pascal
Euclidean plane
Pappus's (hexagon) theorem
degenerate conic
projective plane
line at infinity
polar reciprocal
projective dual
Brianchon's theorem
Blaise Pascal
broadside
Cayley–Bacharach theorem
pole-polar
Gergonne triangle
five points determine a conic
Braikenridge–Maclaurin theorem

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