己知X=2m+1 y=1-2n计算2(x-y)方-(y-x)方-(x+y)(y-x)
问题描述:
己知X=2m+1 y=1-2n计算2(x-y)方-(y-x)方-(x+y)(y-x)
答
2(x-y)方-(y-x)方-(x+y)(y-x)
=(x-y)^2+(x^2-y^2)
=2x^2-2xy
=2x(x-y)
=2(2m+1)(2m+2n)