20 15 Wenzhou senior high school entrance examination mathematics examination paper
Let A(a, 0), P(x, -x), a>0, a>x>0 Because point C and point A are symmetrical about the straight line OP, so point c (0,-a) OP = √ 2x CP = AP = √ [(a-x) 2+x2op+CP+the length LA of AP.