Let a non-isosceles acute triangle ABC with tha attitude AD, BE, CF and the orthocenter H. DE, DF intersect (AD) at M, N respectively. P∈AB,Q∈AC satisfy NP⊥AB,MQ⊥AC
a) Prove that EF is the tangent line of (APQ)
b) Let T be the tangency point of (APQ) with EF,.DT ∩ MN={K}. L is the reflection of A in MN. Prove that MN, EF ,(DLK) pass through a piont geometrygeometric transformationreflection