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Sequence {(1/2)ln(1/n)} converge?

  1. Apr 9, 2008 #1
    1. The problem statement, all variables and given/known data

    Does the sequence {(1/2)ln(1/n)} converge or diverge?

    2. Relevant equations

    Working it out analytically, I think it diverges. I would like to know the appropriate test to show this

    3. The attempt at a solution
  2. jcsd
  3. Apr 9, 2008 #2


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    Seems to me that you can easily show that this diverges from the original definition. I presume that your numerical calculations (I'm not sure what you mean by "analytically". If you have show analytically that this diverges, you are done.) diverges to negative infinity.

    That should lead you to look at (1/2)ln(1/n)< -M for M some large integer. Then ln(1/n)< -2M so 1/n< e-2M[/sum] and n> eM. Working the other way, for any integer M, if n< eM then (1/2)ln(1/n)< -M and so the sequence diverges.
    Last edited: Apr 9, 2008
  4. Apr 9, 2008 #3
    Use the simplest test.

    lim n -> inf gives (1/2)ln(0) which is not defined and clearly not zero. Therefore it diverges.
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