# Math Help - real analysis

1. ## real analysis

Im stuck on this question,do i replace 2n by 2n+1

2. Originally Posted by asingh88
Im stuck on this question,do i replace 2n by 2n+1

It's hard to understand what' written there , but if it is what I think then that seriers converges absolutely: $\sum^\infty_{n=0}\frac{\cos 2n}{2^n-5}$ , since $\left|\frac{\cos 2n}{2^n-5}\right|\leq\frac{1}{2^n-5}$ ...

Tonio