So I've been working on a proof and Wolfram Alpha gives the following partial sum formula for one of the summations in the proof:(adsbygoogle = window.adsbygoogle || []).push({});

http://www.wolframalpha.com/input/?i=sum[e^(-(2k+1)/x)/(1+e^(-(2k+1)/x)+)^2+]

What does the terminology involving psi mean? I think it is the first derivative of the polygamma function, but I don't understand what the subscript e^(2/x) means.

Thanks in advance for the help.

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# Help with polygamma function

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