Let ABCD be a quadrilateral inscribed in circle ω with AC⊥BD. Let E and F be the reflections of D over lines BA and BC, respectively, and let P be the intersection of lines BD and EF. Suppose that the circumcircle of △EPD meets ω at D and Q, and the circumcircle of △FPD meets ω at D and R. Show that EQ=FR. USAJMO2018 USAJMO Problem 3geometrygeometry solvedorthocentereasyevan orz