已知:x-y= -2 求(x2+y2)2-4xy(x2+y2)+4x2y2的值
问题描述:
已知:x-y= -2 求(x2+y2)2-4xy(x2+y2)+4x2y2的值
答
(x2+y2)2-4xy(x2+y2)+4x2y2
=(x^2+y^2-2xy)^2
=(x-y)^4
=(-2)^4
=16