1985 OIM Problems/Problem 6

Revision as of 11:42, 13 December 2023 by Tomasdiaz (talk | contribs) (Created page with "== Problem == Given triangle <math>ABC</math>, we consider the points <math>D</math>, <math>E</math>, and <math>F</math> of lines <math>BC</math>, <math>AC</math>, and <math>A...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Problem

Given triangle $ABC$, we consider the points $D$, $E$, and $F$ of lines $BC$, $AC$, and $AB$ respectively. If lines $AD$, $BE$, and $CF$ all pass through the center $O$ of the circumference of triangle $ABC$, which radius is $r$, proof that: $$ (Error compiling LaTeX. Unknown error_msg)\frac{1}{AD}+\frac{1}{BE}+\frac{1}{CE}=\frac{2}{r}

Solution

This problem needs a solution. If you have a solution for it, please help us out by adding it.