(2n方+2n+1)平方
问题描述：
(2n方+2n+1)平方
答
(2n^2+2n+1)^2=[2n^2+(2n+1)]^2
=4n^4+4n^2*(2n+1)+(2n+1)^2
=4n^4+8n^3+4n^2+4n^2+4n+1
=4n^4+8n^3+8n^2+4n+1