Question

已知正方形ABCD,在BC上任取一点E,连接AE,将三角形ABC绕点B顺时针旋转得到三角形CBF,使AB于CB重合

Answer 1

A(0,8), B(4,0)Q点坐标为x = 4-2tP点坐标为y=4t三角形OPQ面积S=1/2 4t(4-2t) = 2t(4-2t)t=1时,S最大值 S=4C(2,4)OC^2 = 20PQ^2 = (4-2t)^2 + 16t^2 = 20t=1时,PQ^2 = 20OC的斜率为24t/(4-2t) = 1/2t = 0.4时PQ与OC垂...