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Isogonal conjugate

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528: 79: 600: 20: 331: 443: 855: 723: 761: 262: 473:, it makes sense to speak of the isogonal conjugate of sets of points, such as lines and circles. For example, the isogonal conjugate of a line is a 948: 926: 608: 1025: 274: 1010: 356: 774: 1035: 1007: 1050: 112: 958: 474: 470: 687: 899: 728: 229: 223: 527: 8: 644: 943: 907: 1030: 498: 449: 344: 147: 670: 651: 494: 212: 128: 95: 32: 953: 201: 120: 216: 78: 28: 1044: 522: 506: 502: 136: 880: 490: 208: 187: 16:
Geometric transformation applied to points with respect to a given triangle
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Interactive Java Applet illustrating isogonal conjugate and its properties
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in 0, 1, or 2 points. The isogonal conjugate of the circumcircle is the
180: 871:, this conjugate is a generalization of all known kinds of conjugaties: 599: 82:
Isogonal conjugate transformation over the points inside the triangle.
979: 486: 19: 482: 194: 173: 102: 87: 36: 478: 326:{\displaystyle {\tfrac {1}{x}}:{\tfrac {1}{y}}:{\tfrac {1}{z}}.} 647: 611:
given a generalization of isogonal conjugate as follows: Let
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of triangle centers under the trilinear product, defined by
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Another construction for the isogonal conjugate of a point
887:, Dao's generalization become the isogonal conjugate of 146:.) This is a direct result of the trigonometric form of 309: 294: 279: 777: 731: 690: 359: 277: 232: 509:) are self-isogonal-conjugate, in the sense that if 135:. (This definition applies only to points not on a 849: 755: 717: 437: 325: 256: 1042: 61:reflected about the angle bisectors (concur at 1008:César Eliud Lozada, Preamble before X(44687) 333:For this reason, the isogonal conjugate of 127:respectively. These three reflected lines 676:If barycentric coordinates of the center 531:A second definition of isogonal conjugate 438:{\displaystyle (p:q:r)*(u:v:w)=pu:qv:rw,} 264:is a point not on a sideline of triangle 179:is itself. The isogonal conjugate of the 1003: 1001: 977: 850:{\displaystyle D=D(X,P)=x*(x-y-z)*q*r::} 598: 526: 77: 18: 219:are isogonal conjugates of each other. 1043: 1036:Pedal Triangle and Isogonal Conjugacy 998: 489:according as the line intersects the 13: 980:"Constructing Isogonal Conjugates" 906:, Dao's generalization become the 153:The isogonal conjugate of a point 14: 1062: 1019: 594: 271:, then its isogonal conjugate is 207:. The isogonal conjugates of the 1011:Encyclopedia of Triangle Centers 925:Dao's generalization become the 569:. Then the center of the circle 193:. The isogonal conjugate of the 48: Lines from each vertex to 767:, the point of intersection of 971: 829: 811: 799: 787: 402: 384: 378: 360: 172:The isogonal conjugate of the 1: 964: 587:is the isogonal conjugate of 469:As isogonal conjugation is a 131:at the isogonal conjugate of 161:. The isogonal conjugate of 7: 937: 10: 1067: 452:, and the inverse of each 666:respectively. Then lines 619:a point on its plane and 546:, let the reflections of 539:in the plane of triangle 718:{\displaystyle X=x:y:z:} 337:is sometimes denoted by 157:is sometimes denoted by 959:Central line (geometry) 921:is the circumconic of 756:{\displaystyle P=p:q:r} 257:{\displaystyle X=x:y:z} 200:is (by definition) the 851: 757: 719: 604: 532: 519:is also on the cubic. 513:is on the cubic, then 497:. Several well-known 439: 327: 258: 83: 75: 900:Steiner circumellipse 852: 758: 720: 602: 530: 440: 328: 259: 224:trilinear coordinates 81: 22: 775: 729: 688: 603:X-Dao conjugate of P 357: 275: 230: 215:and vice versa. The 477:; specifically, an 944:Isotomic conjugate 908:isotomic conjugate 867:-Dao conjugate of 847: 753: 715: 643:respectively, and 605: 535:For a given point 533: 435: 323: 318: 303: 288: 254: 111:is constructed by 101:with respect to a 92:isogonal conjugate 84: 76: 67:isogonal conjugate 1051:Triangle geometry 550:in the sidelines 505:, Darboux cubic, 450:commutative group 317: 302: 287: 213:isodynamic points 1058: 1013: 1005: 996: 995: 993: 991: 975: 932: 924: 920: 913: 905: 897: 890: 886: 878: 870: 866: 862: 856: 854: 853: 848: 770: 766: 762: 760: 759: 754: 724: 722: 721: 716: 683: 679: 669: 665: 661: 657: 642: 638: 634: 630: 622: 618: 614: 590: 586: 568: 553: 549: 545: 538: 518: 512: 495:line at infinity 465: 459: 455: 444: 442: 441: 436: 349: 342: 336: 332: 330: 329: 324: 319: 310: 304: 295: 289: 280: 270: 263: 261: 260: 255: 206: 199: 192: 185: 178: 168: 164: 160: 156: 145: 134: 126: 118: 110: 100: 72: 64: 60: 56: 51: 47: 41: 26: 1066: 1065: 1061: 1060: 1059: 1057: 1056: 1055: 1041: 1040: 1022: 1017: 1016: 1006: 999: 989: 987: 986:. GeoGebra Team 976: 972: 967: 954:Triangle center 949:Polar conjugate 940: 930: 927:Polar conjugate 922: 918: 911: 903: 895: 888: 884: 876: 868: 864: 863:above call the 860: 776: 773: 772: 768: 764: 730: 727: 726: 689: 686: 685: 681: 677: 667: 663: 659: 655: 640: 636: 632: 628: 620: 616: 615:be a triangle, 612: 597: 588: 584: 580: 576: 570: 567: 563: 559: 555: 551: 547: 540: 536: 525: 514: 510: 461: 457: 453: 358: 355: 354: 347: 338: 334: 308: 293: 278: 276: 273: 272: 265: 231: 228: 227: 204: 202:symmedian point 197: 190: 183: 176: 166: 162: 158: 154: 140: 132: 124: 121:angle bisectors 116: 105: 98: 74: 70: 62: 58: 57: Lines to 54: 52: 49: 45: 43: 39: 29:Angle bisectors 24: 17: 12: 11: 5: 1064: 1054: 1053: 1039: 1038: 1033: 1028: 1021: 1020:External links 1018: 1015: 1014: 997: 978:Steve Phelps. 969: 968: 966: 963: 962: 961: 956: 951: 946: 939: 936: 935: 934: 915: 892: 846: 843: 840: 837: 834: 831: 828: 825: 822: 819: 816: 813: 810: 807: 804: 801: 798: 795: 792: 789: 786: 783: 780: 752: 749: 746: 743: 740: 737: 734: 714: 711: 708: 705: 702: 699: 696: 693: 650:through these 596: 595:Generalization 593: 582: 578: 574: 565: 561: 557: 524: 521: 503:Thompson cubic 446: 445: 434: 431: 428: 425: 422: 419: 416: 413: 410: 407: 404: 401: 398: 395: 392: 389: 386: 383: 380: 377: 374: 371: 368: 365: 362: 322: 316: 313: 307: 301: 298: 292: 286: 283: 253: 250: 247: 244: 241: 238: 235: 217:Brocard points 148:Ceva's theorem 53: 44: 23: 15: 9: 6: 4: 3: 2: 1063: 1052: 1049: 1048: 1046: 1037: 1034: 1032: 1029: 1027: 1024: 1023: 1012: 1009: 1004: 1002: 985: 981: 974: 970: 960: 957: 955: 952: 950: 947: 945: 942: 941: 928: 916: 909: 901: 893: 882: 874: 873: 872: 857: 844: 841: 838: 835: 832: 826: 823: 820: 817: 814: 808: 805: 802: 796: 793: 790: 784: 781: 778: 769:AA", BB", CC" 750: 747: 744: 741: 738: 735: 732: 712: 709: 706: 703: 700: 697: 694: 691: 674: 672: 668:AA", BB", CC" 653: 649: 646: 626: 623:an arbitrary 610: 609:Dao Thanh Oai 607:In may 2021, 601: 592: 585: 544: 529: 520: 517: 508: 507:Neuberg cubic 504: 500: 496: 492: 488: 484: 480: 476: 472: 467: 464: 451: 432: 429: 426: 423: 420: 417: 414: 411: 408: 405: 399: 396: 393: 390: 387: 381: 375: 372: 369: 366: 363: 353: 352: 351: 346: 341: 320: 314: 311: 305: 299: 296: 290: 284: 281: 269: 251: 248: 245: 242: 239: 236: 233: 225: 220: 218: 214: 210: 209:Fermat points 203: 196: 189: 182: 175: 170: 151: 149: 144: 138: 130: 122: 114: 109: 104: 97: 93: 89: 80: 68: 38: 34: 30: 21: 988:. Retrieved 983: 973: 881:circumcircle 858: 675: 606: 572: 542: 534: 515: 491:circumcircle 468: 462: 447: 339: 267: 221: 188:circumcentre 171: 152: 142: 139:of triangle 107: 91: 85: 66: 625:circumconic 475:circumconic 181:orthocentre 990:17 January 965:References 859:The point 664:A", B", C" 656:BC, CA, AB 641:A', B', C' 635:cut again 633:AP, BP, CP 552:BC, CA, AB 119:about the 117:PA, PB, PC 115:the lines 113:reflecting 1031:MathWorld 839:∗ 833:∗ 824:− 818:− 809:∗ 671:concurent 662:again at 487:hyperbola 382:∗ 1045:Category 984:GeoGebra 938:See also 645:parallel 631:. Lines 483:parabola 471:function 211:are the 195:centroid 174:incentre 137:sideline 103:triangle 88:geometry 37:incenter 898:is the 879:is the 763:, then 501:(e.g., 479:ellipse 343:. The 186:is the 125:A, B, C 652:points 499:cubics 129:concur 90:, the 65:, the 55:  46:  33:concur 27:  25:  917:When 894:When 875:When 648:lines 629:△ ABC 613:△ ABC 485:, or 448:is a 226:, if 96:point 94:of a 992:2022 771:is: 725:and 684:are 658:cut 929:of 923:ABC 910:of 904:ABC 902:of 885:ABC 883:of 680:of 654:to 639:at 627:of 564:, P 560:, P 554:be 543:ABC 460:is 456:in 345:set 268:ABC 222:In 165:is 143:ABC 123:of 108:ABC 86:In 69:of 35:at 1047:: 1000:^ 982:. 845::: 673:. 591:. 481:, 466:. 169:. 163:P* 159:P* 150:. 63:P* 994:. 933:. 931:P 919:Ω 914:. 912:P 896:Ω 891:. 889:P 877:Ω 869:P 865:X 861:D 842:r 836:q 830:) 827:z 821:y 815:x 812:( 806:x 803:= 800:) 797:P 794:, 791:X 788:( 785:D 782:= 779:D 765:D 751:r 748:: 745:q 742:: 739:p 736:= 733:P 713:: 710:z 707:: 704:y 701:: 698:x 695:= 692:X 682:Ω 678:X 660:Ω 637:Ω 621:Ω 617:P 589:P 583:c 581:P 579:b 577:P 575:a 573:P 571:〇 566:c 562:b 558:a 556:P 548:P 541:△ 537:P 516:X 511:X 463:X 458:S 454:X 433:, 430:w 427:r 424:: 421:v 418:q 415:: 412:u 409:p 406:= 403:) 400:w 397:: 394:v 391:: 388:u 385:( 379:) 376:r 373:: 370:q 367:: 364:p 361:( 348:S 340:X 335:X 321:. 315:z 312:1 306:: 300:y 297:1 291:: 285:x 282:1 266:△ 252:z 249:: 246:y 243:: 240:x 237:= 234:X 205:K 198:G 191:O 184:H 177:I 167:P 155:P 141:△ 133:P 106:△ 99:P 73:) 71:P 59:P 50:P 42:) 40:I 31:(

Index


Angle bisectors
concur
incenter

geometry
point
triangle
reflecting
angle bisectors
concur
sideline
Ceva's theorem
incentre
orthocentre
circumcentre
centroid
symmedian point
Fermat points
isodynamic points
Brocard points
trilinear coordinates
set
commutative group
function
circumconic
ellipse
parabola
hyperbola
circumcircle

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