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Help needed with the ratio test

  1. Dec 1, 2009 #1
    1. The problem statement, all variables and given/known data

    The problem is looking for the radius of convergence
    sum(5^n)((x-3)^n)/n
    n=1
    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Dec 1, 2009 #2

    Mark44

    Staff: Mentor

    What work have you done in using the ratio test?
     
  4. Dec 1, 2009 #3
    I broke it down to (x-3)n/(n+1)
     
  5. Dec 1, 2009 #4

    Mark44

    Staff: Mentor

    That's not right. What happened to the 5^n factor?
    You should have this as part of your work.
    [tex]\lim_{n \to \infty} \left(\frac{5^{n + 1}(x - 3)^{n + 1}}{n + 1}~\frac{n + 1}{5^n (x - 3)^n}\right )[/tex]
     
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