计算:4/ (x+1)(x+3)+4/(x+3)(x+5)+…..+4/(x+2n-1)(x+2n+1)的值?

问题描述:

计算:4/ (x+1)(x+3)+4/(x+3)(x+5)+…..+4/(x+2n-1)(x+2n+1)的值?
能不能说详细一点哟——fish俊

4/ (x+1)(x+3)=2/(x+1) -2/(x+3)
4/ (x+1)(x+3)+4/(x+3)(x+5)+…..+4/(x+2n-1)(x+2n+1)
=2/(x+1) -2/(x+2n+1)