化简：(x^4+x^3y-xy^3-y^4)/(x^4-x^3y+x^2y^2+xy^3-2y^4)
问题描述：
化简：(x^4+x^3y-xy^3-y^4)/(x^4-x^3y+x^2y^2+xy^3-2y^4)
答
分子=(x+y)(x-y)(x^2+xy+y^2)
分母=(x-y)(x+y)(x^2-xy+2y^2)
所以化简后为(x^2+xy+y^2)/(x^2-xy+2y^2)