实验班上有题是这样的:若a=-2,b=-1/2,则2^2n*(ab^n+1)^2

问题描述:

实验班上有题是这样的:若a=-2,b=-1/2,则2^2n*(ab^n+1)^2

答案是1
将a=-2,b=-1/2代入原式,
得原式=(-2)^2n*(-2)^2*[(-1/2)^2]^n+1
=2^2n*4*(1/4)n+1
=2^2n*(1/4*4)*(1/4)^n
=2^2n*(1/4)^n
=(2*2*1/4)^n
=1^n
=1