首页 > 留学知识库

问题: 二项式定理,救救我,明天要交

化简
(2x+y)^4-(2x-y)^4

解答:

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

=[(2x+y)^2]^2-[(2x-y)^2]^2
=[(2x+y)^2+(2x-y)^2][(2x+y)^2-(2x-y)^2]
=[4x^2+2y^2][(2x+y)+2x-y)][(2x+y)-(2x-y)]
=2(2x+y)*4x*2y
=16xy(2x+y)