Παρασκευή 15 Μαρτίου 2013

Pedal and Antipedal Circles tangent

Are there real points P such that the pedal and antipedal circles of P are tangent?

Antreas P. Hatzipolakis, Hyacinthos #21746

------------------------------------

I get the cubic

S^2 xyz + CyclicSum[ a^2 y z (c^2 y + b^2 z)] = 0.

Francisco Javier, Hyacinthos #21747

------------------------------------

Yes, if P is on an octic or on the cubic K191="circumcircle pedal cubic, nK(X6, X6,?)".

If P is on the cubic K191, then the point of the contact of the two circles are on the circumcircle.

K191: S^2 xyz + CyclicSum[ a^2 y z (c^2 y + b^2 z)] = 0,

or equivalently

K191: S^2 xyz + CyclicSum[ a^2 x (c^2 y^2 + b^2 z^2)] = 0.

S= 2*area(ABC) (In CTC of Bernad Gibert, S=area(ABC))

Angel Montesdeoca, Hyacinthos #21750

The cubic S^2 xyz + CyclicSum[ a^2 y z (c^2 y + b^2 z)] = 0 is not K191

It will be K634 in Bernard Gibert's list

Δεν υπάρχουν σχόλια:

Δημοσίευση σχολίου

ETC1

X(73143) = X(5)X(14385)∩X(50)X(3018) Barycentrics    (a^2 - b^2 - c^2)*(a^10 + a^8*b^2 - 2*a^6*b^4 - 2*a^4*b^6 + a^2*b^8 + b^10 - 4*a^8*c^...