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Power series expansion

  1. Dec 7, 2004 #1
    I was wondering how to create a power series expansion for the function
    x^2 / (1+x^2).... I've tried using the geometric series, but somehow i got stuck.
  2. jcsd
  3. Dec 7, 2004 #2


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    Geometric series should work fine. How about you post your work?

    An alternate method: if you know the series for arctan(x), you can use the fact that it's derivative is 1/(1+x^2).
  4. Dec 8, 2004 #3
    It may also help you to think in what form geometric series are usually in, i.e.

    1/(1-r). So maybe altering your fraction a bit will help you notice it.
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