Derivative of Gamma Function at 1/Proof 1

Proof
From Reciprocal times Derivative of Gamma Function:


 * $\displaystyle \dfrac {\Gamma' \left({z}\right)} {\Gamma \left({z}\right)} = -\gamma + \sum_{n \mathop = 1}^\infty \left({\frac 1 n - \frac 1 {z + n - 1} }\right)$

Setting $n = 1$: