INTEGRAL xln(z^2+x^2)/e^{2 \pi x}-1\,dx
In this post we will compute the following three integrals: Consider the following three integrals (1) (2) (3) Differentiating the three w.r. to z we obtain (4) (5) (6) Now recall Binet´s Integral representation for the Digamma function (7) Making the change of variable and multiplying (7) by 4z we get (8) Multiplying (3) by (9) Integrating (8) w.r. to z Letting Where we used that Proved here . For the second integral, integrating from 0 to z Letting Where we used that Proved here . For the last integral, We Multiply both sides of (7) by to get Now let And now let to obtain Integrating from 0 to z Letting