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Homework Help: Proof of Divergence of a Series

  1. Mar 24, 2013 #1
    Prove that the series [itex]\displaystyle\sum_{k=1}^{\infty}\sqrt[k]{k+1}-1[/itex] diverges.

    I thought that I could show the [itex]n^{th}[/itex] term was greater than [itex]\frac{1}{n}[/itex] but this is turning out to be more difficult than I imagined. Is there a neat proof that [itex]n^n>(n+1)^{n-1}[/itex]?
     
  2. jcsd
  3. Mar 24, 2013 #2

    Dick

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    ##(k+1)^\frac{1}{k}=\exp(\log((k+1)^\frac{1}{k}))##. Simplify the log a little and think about what the series expansion of ##e^x## looks like.
     
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