Question

（2m-n)ˆ(2m+n)ˆ2(nˆ2+4mˆ2)ˆ2

Answer 1

第一道全是幂的形式么、没看懂

第二道=(x+y)(x-y)(x+y)(x-y)-(x^2-y^2)(x^2+y^2)=(x^2-y^2)(x^2-y^2)-(x^2-y^2)(x^2+y^2)=(x^2-y^2)(x^2-y^2-x^2-y^2)=-2y^2(x^2-y^2)