联立抛物线y^2=2px和直线y=x-2p 交点坐标分别为(x1,y1),(x2,y2)
x^2-6px+4p^2=0
x1*x2=4p^2,x1+x2=6p y1y2=x1x2-2p(x1+x2)+4p^2
x1x2+y1y2=8p^2-12p^2不等于零
有问题