Second integral representation of digamma proof

$$\psi(s+1)\,=\, -\gamma \,+\, \int^{1}_{0}\frac{1-x^s}{1-x}\,dx$$

$$\textit{proof}$$
This can be done by noting that

$$\psi(s+1) = -\gamma +\sum_{n=1}^\infty\frac{s}{n(n+s)}$$

It is left as an exercise to prove that

$$\sum_{n=1}^\infty\frac{s}{n(n+s)} = \int^{1}_{0}\frac{1-x^s}{1-x}\,dx$$

This entry was posted in Digamma function and tagged , , . Bookmark the permalink.

Leave a Reply