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Homework Help: Sum somewhat similar to Basel problem?

  1. Oct 6, 2014 #1
    1. The problem statement, all variables and given/known data
    For a problem in quantum, I am finding the probability of a particle initially in the ground state on a circular loop of length L being in the nth state of the string after it is cut (becomes an infinite square well, and we assume the wavefunction is not disturbed during this cutting). I believe I found this probability, and am now trying to show that the sum over all possible states is 1. This is where I am stuck. I have

    2. Relevant equations
    ## P_{n=odd}=\frac{16}{\pi^2}\frac{n^2}{(n^2-4)^2} ##
    ## P_{n=even}=0 ##
    And maybe
    ## \sum_{n=1}^{\infty}=\frac{\pi^2}{6} ##
    3. The attempt at a solution
    The solution I have was getting thus far, and I am fairly confident in it. I do not expect a solution, just a point in the right direction. I did attempt to write my probability as a derivative of n, but that led to another dead end fairly quickly.
  2. jcsd
  3. Oct 6, 2014 #2
    Nevermind, figured it out!!
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