In this post we will prove the following result We start by recalling Hermite´s integral representation of the Hurwitz zeta function (proved here ) (1) We may rewrite it in a slightly different way which facilitates some calculations, to this end we start with the following lemma: Lemma: Proof: We can therefore rewrite (1) as (2) Differentiating (2) w.r. to s we obtain (3) Letting and using the logarithmic representation of arctan we obtain rearranging terms we get: Now let to obtain Which concludes the proof. Note: In the proof above we used the following previously established results Proved here Proved here Proved here