Problem

Source: Federal Mathematical Competition of Serbia and Montenegro 2004

Tags: geometry



In a triangle $ABC$, points $D$ and $E$ are taken on rays $CB$ and $CA$ respectively so that $CD=CE = \frac{AC+BC}{2}$. Let $H$ be the orthocenter of the triangle, and $P$ be the midpoint of the arc $AB$ of the circumcircle of $ABC$ not containing $C$. Prove that the line $DE$ bisects the segment $HP$.