# Determing range of x for which series converges or diverges

1. Apr 21, 2007

### pablito21

im trying to solve this excersice but i couldnt find any similar questions like this one

find for which real x the series SIGMA x^n/1+x^2n converges and for which it diverges

2. Apr 21, 2007

### mathman

Your expression involving x is ambiguous. I suggest you put parentheses in to clarify the order for division and addition.

3. Apr 21, 2007

### AlphaNumeric

Assuming it's supposed to be $$\sum_{n=1}^{infinity} \frac{x^{n}}{1+x^{2n}}$$, you can use the ratio test to compute when it's convergent or not. Just by judging 'large n behaviour' you should be able to narrow down the possible interesting values of x pretty quickly.