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Darboux Cubic


DarbouxCubic

Darboux cubic Z(X_(20)) of a triangle DeltaABC is the locus of all pedal-cevian points (i.e., of all points whose pedal triangle is perspective with DeltaABC). 它是 self-isogonal cubic,其支点由 de Longchamps point L (Kimberling center X_(20)) 给出。 因此,它具有参数 x=cosA-cosBcosC 和三线方程

 (cosA-cosBcosC)alpha(beta^2-gamma^2)+(cosB-cosCcosA)beta(gamma^2-alpha^2)+(cosC-cosAcosB)gamma(alpha^2-beta^2)=0

(Cundy and Parry 1995)。

Darboux cubic 关于外心 O 对称,因此如果 P 位于 cubic 上,那么 P 关于 Oreflection 也位于 cubic 上。

它穿过 Kimberling centers X_i,其中 i=1 (incenter I), 3 (circumcenter O), 4 (orthocenter H), 20 (de Longchamps point L), 40 (Bevan point V), 64 (the isogonal conjugate of the de Longchamps point), 84 (the isogonal conjugate of the Bevan point) (Kimberling 1998, p. 240), 1490, 1498, 2130, and 2131。


参见

Lucas Cubic, Self-Isogonal Cubic, Triangle Cubic

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参考文献

Cundy, H. M. and Parry, C. F. "Some Cubic Curves Associated with a Triangle." J. Geom. 53, 41-66, 1995.Gibert, B. "Darboux Cubic." http://perso.wanadoo.fr/bernard.gibert/Exemples/k004.html.Kimberling, C. "Triangle Centers and Central Triangles." Congr. Numer. 129, 1-295, 1998.Rubio, P. "Cubic Lines Relative to a Triangle." J. Geom. 34, 152-171, 1989.

在 Wolfram|Alpha 上被引用

Darboux Cubic

请引用为

Weisstein, Eric W. "Darboux Cubic." 来自 MathWorld--Wolfram Web 资源。 https://mathworld.net.cn/DarbouxCubic.html

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