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Power series

  1. Mar 23, 2010 #1
    how can i find a power series representaion of d/dx (1/x-9)
  2. jcsd
  3. Mar 23, 2010 #2
    You can find an approximation by calculating the Taylor series around some point (a=0 would probably be easiest). All you need to do is find derivatives of the function up to the nth derivative, depending on how accurate you want the representation to be, and substitute them into the general series given http://en.wikipedia.org/wiki/Taylor_series" [Broken].
    Last edited by a moderator: May 4, 2017
  4. Mar 23, 2010 #3


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    It looks like you may have some sort of a typo. At x=0, 1/x is infinite.
  5. Mar 23, 2010 #4
    I mean for it to say d/dx (1/(x-9)) sorrry
  6. Mar 23, 2010 #5


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    This expression can be written as -1/9 * d/dx (1/(1-x/9)). Then think geometric series. Can you see it from there?
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