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Homework Help: Convergence of a series help

  1. Oct 31, 2013 #1
    1. The problem statement, all variables and given/known data

    Determine whether the following are convergent, divergent or oscillating.

    2. Relevant equations

    Please see the attachment

    3. The attempt at a solution

    Please see the attachment. Im unsure about this as when I plot a graph without K its convergence

    Attached Files:

    Last edited: Oct 31, 2013
  2. jcsd
  3. Oct 31, 2013 #2


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    Homework Helper

    You haven't applied the ratio test correctly. You have
    \lim_{i \to \infty} \left|\frac{a_{i+1}}{a_i}\right| = \lim_{i \to \infty} \left(\frac{i + 1}{i}\right)^2 e^{-K}
    which is correct. But then you don't try to find the limit, which is what you need to apply the ratio test.
  4. Oct 31, 2013 #3
    How would I go about finding the limit?
  5. Oct 31, 2013 #4
  6. Oct 31, 2013 #5
    Mmmm.. still not sure, am I going about it in the right direction, does it seem divergent?
  7. Oct 31, 2013 #6


    Staff: Mentor

    Rather than guess whether the series is divergent or convergent, why don't you finish your work on the limit?
  8. Oct 31, 2013 #7
    I thought I had finished, is there something im missing?
  9. Oct 31, 2013 #8
    Can you find the limit of post #2?
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