这不是立方差公式么？等于x^6-y^6
(x^2-y^2)(x^4+x^2y^2+y^4)=(x^2-y^2)(x^4+2x^2y^2+y^4-x^2y^2)=(x^2-y^2)[(x^2+y^2)^2-x^2y^2]=(x+y)(x-y)(x^2+y^2+xy)(x^2+y^2-xy)
(x^2-y^2)(x^4+x^2y^2+y^4)=(x+y)(x-y)(x^4+x^2y^2+y^4)
