|a+2I=0,求-5(a+1)^2n*7(a+2)^n+1-3(a+3)^2n+1的值(其中n为正整数).
问题描述:
|a+2I=0,求-5(a+1)^2n*7(a+2)^n+1-3(a+3)^2n+1的值(其中n为正整数).
答
|a+2|=0,
a+2=0,
a=-2
-5(a+1)^2n*7(a+2)^n+1-3(a+3)^2n+1
=-5(-2+1)^2n*7(-2+2)^n+1-3(-2+3)^2n+1
=-5*0+3
=3
答
|a+2|=0
则a+2=0
a+3=0+1=1
所以原式=-5(a+1)^2n*0-3*1^(2n+1)
=0-3*1
=-3