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$$\frac{2}{1^p}\ + \frac{3}{2^p}\ + \frac{4}{3^p}\ +\ldots\,.$$

I can see that the $nth$ term is $\frac{n+1}{n^p}$

How do I test for its convergence?

JimmyK4542
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Diya
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1 Answers1

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Hint: $\displaystyle\sum_{n=1}^{\infty}\dfrac{n+1}{n^p} = \sum_{n=1}^{\infty}\left[\dfrac{n}{n^p}+\dfrac{1}{n^p}\right] = \sum_{n=1}^{\infty}\left[\dfrac{1}{n^{p-1}}+\dfrac{1}{n^p}\right]$. Now apply the $p$-test.

JimmyK4542
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  • I don't know what the p is here, how will I apply the p-series test? – Diya Aug 27 '14 at 03:43
  • Convergence will depend on the value of $p$. So your answer will be something like "The series converges for [conditions on $p$] and diverges for [opposite conditions on $p$]". – JimmyK4542 Aug 27 '14 at 03:46
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    Ok then! Divergent for $p<=2$ and convergent for $p>2$ – Diya Aug 27 '14 at 03:49