Monday, 28 November 2016

Determine the sum of the given series



I'm trying to find the sum of this series, but I'm not sure how to go about doing that. Based on the Direct Comparison Test, I've found that this function converges, but I don't know how to find it's sum. Any help would greatly be appreciated.



Rusty $$\sum_{n=1}^\infty \dfrac6{n(n+3)}.$$



Answer



Hint



Use partial fraction decomposition to get $$\frac{6}{n (n+3)}=2(\frac{1}{n} -\frac{1}{n+3})$$ and check if, by chance, they do not telescope.


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