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MathNet 2016-part-05 — 184 problems (EN–VI) Question 8

Math Olympiad Vault · MathNet 2016-part-05 — 184 problems (EN–VI)

Question 8

Let $ABC$ be a triangle and $I$ its incenter. The point $D$ is on segment $BC$ and the circle $\omega$ is tangent to the circumcircle of triangle $ABC$ but is also tangent to $DC$, $DA$ at $E$, $F$, respectively. Prove that $E$, $F$ and $I$ are collinear.