Friday, September 8, 2017

sequences and series - How do i evaluate this sum :$sum _{m=1}^{infty } sum _{k=1}^{infty } frac{m(-1)^m(-1)^klog(m+k)}{(m+k)^3}$?

How do I evaluate the following sum:


$$\sum _{m=1}^{\infty } \sum _{k=1}^{\infty } \frac{m(-1)^m(-1)^k\log(m+k)}{(m+k)^3}$$


Note I used many idea such as :Hochino's Idea and taylor expansion of


$\log(1+x)$ at $x=1$ where $x=\frac{k}{m}$ ,but those methods not work .


and also i tried to write $\log(m+k)$ as a power series but it became to me as a


triple series then it is very complicated for evaluation !!!


Thank you for any help

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