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Finding a Closed Form from a Power Series

  1. Dec 16, 2006 #1
    1. The problem statement, all variables and given/known data

    I have f(x) = the series x^k/[(k-1)k] summed from x=2 to infinity, and I need to find its closed form. Hint: What is the derivative of f(x)

    2. Relevant equations


    3. The attempt at a solution

    To start this problem, I took the derivative of the series, which makes the general term x^(k-1)/(k-1), which is x + x^2/2 + x^3/3... How do I get a function from this? I know this series looks really familiar, but I can't seem to remember where I've seen it before.
  2. jcsd
  3. Dec 16, 2006 #2


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    Homework Helper

    Take the derivative one more time.
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