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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,其支點由 de Longchamps point L (Kimberling center X_(20)) 給出。 因此,它具有引數 x=cosA-cosBcosC 和三線方程

 (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 關於外心 O 對稱,因此如果 P 位於 cubic 上,那麼 P 關於 Oreflection 也位於 cubic 上。

它穿過 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。


參見

Lucas Cubic, Self-Isogonal Cubic, Triangle Cubic

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參考文獻

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 上被引用

Darboux Cubic

請引用為

Weisstein, Eric W. "Darboux Cubic." 來自 Web 資源。 https://mathworld.tw/DarbouxCubic.html

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