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Determing range of x for which series converges or diverges

  1. Apr 21, 2007 #1
    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. jcsd
  3. Apr 21, 2007 #2


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    Your expression involving x is ambiguous. I suggest you put parentheses in to clarify the order for division and addition.
  4. Apr 21, 2007 #3
    Assuming it's supposed to be [tex]\sum_{n=1}^{infinity} \frac{x^{n}}{1+x^{2n}}[/tex], 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.
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