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Prove that AY is tangent to (AEF)

Source: IMOC 2021 G8

August 11, 2021
geometrytangent

Problem Statement

Let PP be an arbitrary interior point of ABC\triangle ABC, and APAP, BPBP, CPCP intersect BCBC, CACA, ABAB at DD, EE, FF, respectively. Suppose that MM be the midpoint of BCBC, (AEF)\odot(AEF) and (ABC)\odot(ABC) intersect at SS, SDSD intersects (ABC)\odot(ABC) at XX, and XMXM intersects (ABC)\odot(ABC) at YY. Show that AYAY is tangent to (AEF)\odot(AEF).