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Showing posts with the label Ramanujan

Infinite sum reciprocal hyperbolic sine squared

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This is a short article to prove the following result To this end we will rely on some previous established results, namely: proved here, and proved here . As a corollary of our goal series we also obtain this nice series Click here  for the proof of our main series.

Lattice sums

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In this entry we will evaluate symmetric infinite sums of the type To this end we will rely on the previous established result ( proved here ) Click here for the proof.

Two remarkable sums due to Ramanujan-Part II

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In this entry we present a second proof via contour integration for the series (proved previously here ) Click here for the proof.

Two remarkable sums due to Ramanujan-Part I

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In this article we prove two remarkable results due to Ramanujan, namely and To this end we rely on the functional equation that the Dedekind´s eta function obeys, previously proved ( here ): Click here for the proof.

A Ramanujan Series

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In this article we prove the following Ramanujan series To this end we will rely on the residues theorem.  Click here  for the proof of the Ramanujan´s series

RAMANUJAN´S INFINITE SUM

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Today we will proof the following two beautiful results found here . The first one is known to be an infinite sum proved by Ramanujan to Hardy, the second I am not sure. (1) (2) First, recall the partial fraction expansion of the hyperbolic cotangent Then we first sum becomes Since n and k are dummy variables, we can re-index the second double sum exchanging n by k and vice versa, then For the second sum