Question

(x+y)^4+x^4+y^4 因式分解

Answer 1

原式=(x^2+y^2)2-2x^2y^2+(x+y)^4

=[(x+y)^2-2xy]^2-2x^2y^2+(x+y)^4

=2(x+y)^4-4xy(x+y)^4+2x^2y^2

=2[(x+y)^2-xy]^2

=2(x^2+xy+y^2)^2