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Homework Help: Radius of Convergence

  1. Sep 29, 2010 #1
    1. The problem statement, all variables and given/known data

    See figure attached for problem statement as well as my attempt.

    2. Relevant equations

    3. The attempt at a solution

    See 2nd figure attached.

    I don't know how to rid myself of that last n! I've got kicking around in the numerator.

    Any ideas?

    Attached Files:

  2. jcsd
  3. Sep 29, 2010 #2


    User Avatar

    Check your an+1 term. The [(n+1)!] should be squared.
  4. Sep 29, 2010 #3

    Thank you!
  5. Sep 29, 2010 #4
    Just to make sure I finished the question off right, we should find that R = -1, correct?

    Then the open interval of convergence is,

    [tex]|x-7| < -1[/tex]

    or [tex] 1 < x-7 < -1[/tex] or [tex] 8 < x < 6[/tex]
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