当x=2012,y=-2011时,求代数式(x^4-y^4)/(x2-2xy y2)·(y-x)/(x2 y2)

问题描述:

当x=2012,y=-2011时,求代数式(x^4-y^4)/(x2-2xy y2)·(y-x)/(x2 y2)

(x^4-y^4)/(x2-2xy+ y2)·(y-x)/(x2+ y2)
=(x^2-y^2)(x^2+y^2)/(x-y)²·(y-x)/(x2+y2)
=-(x+y)
=-(2012-2011)
=-1