(x+y+z)^2-(x-y-z)^2(a-b)^n+2 -(a-b)^n

问题描述:

(x+y+z)^2-(x-y-z)^2
(a-b)^n+2 -(a-b)^n

zijixiang

曹操曹操曹操曹操曹操曹操曹操曹操

(1)原式=x^2+y^2+z^2+2xy+2xz+2yz-(x^2+y^2+z^2-2xy-2xz-2yz)=4xy+4xz+4yz
(2)原式=(a-b)^2=a^2+b^2+2ab