(x-y)平方-(y-x)平方
=0
a(x-y)n次方-3b(y-x)n+1次方+2c(y-x)n+2次方
=(x-y)^n[a-3b(y-x)+2x(y-x)^2] (n是偶数)
=(x-y)^n[a+3b(y-x)-2x(y-x)^2] (n是奇数)那个……啥，我第一题打错了，后面是立方，亲~回答一下吧(x-y)^3-(y-x)^3=(x-y)^3+(x-y)^3=2(x-y)^3