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Showing posts with the label Infinite Series

Infinite series involving sech squared PART II

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In this post we prove the following infinite sum Click here for the proof. We relied in a few previous established results: Proved here Both proved here . And Proved here .

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.

Infinite series involving hyperbolic cotangent

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In this article we want to prove the following three infinte series: click here for the proof.

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.

Summing some Eisenstein series

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In this blog entry we will prove the following three beautifull infinte series Click here for the proof.

An alternate infinite series involving sinh(n \pi)

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In this entry we present a proof via contour integration for the following alternate infinite series 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

POISSON SUMMATION COSH SUM

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We want to prove the following transformation formula that appears in this twitter post Click here to see the proof . We used the result proved here .

Derivative of Dirichlet Eta function @ 1

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          Today we will evaluate the following infinite sum which corresponds to the derivative of Dirichlet eta function @ 1 As a bonus we will compute the following integral Lets first introduce a lemma: Lemma 1: (1) Proof: Claim: (2) If we let     in (1) we get (3) Lets now recall the Euler Maclaurin Formula (proved here ) to estimate the last two sums above (4) Choosing    and         in (4), we get for the first sum : (5) And for the second sum (6) Recall also the integral representation of the Stiltjies constant (shown here ): (7) letting in (7) we obtain (8) Now, plugging (5) and (6) back in (3) and letting we obtain We can now use (2) to calculate the following integral Proof:

FUNCTIONAL EQUATION FOR THE HURWITZ ZETA FUNCTION

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          In today´s post we will derive a functional equation for the Hurwitz Zeta Function, namely: To this end we introduce the periodic zeta function defined by the following expression: (1) Theorem 1: (2) for and Proof: First recall the previously proved fourier expansion (see here ) (3) for and Now lets expand (2) by means of Euler´s formula Lemmma 1: Let h and k be two integers, , then for (4) Proof: To prove this equality used in the proof above Lets expand first it´s L.H.S. We used the fact that for m an integer Now, lets expand it´s R.H.S. and show that they are equal to each other Theorem 2: If k and h are integers with , then for all s we have Proof: Plugging (4) in (2) we obtain: