Content deleted Content added
R. J. Mathar (talk | contribs) →Gauss's digamma theorem: another link for derivation of Gauss theoerm |
R. J. Mathar (talk | contribs) |
||
Line 370:
:<math>\operatorname{Im} \psi(\tfrac{1}{2}+bi) = \frac{\pi}{2}\tanh (\pi b).</math>
Apart from Gauss's digamma theorem, no such closed formula is known for the real part in general. We have, for example, at the [[imaginary unit]] the numerical approximation {{OEIS2C|A248177}}
:<math>\operatorname{Re} \psi(i) = -\gamma-\sum_{n=0}^\infty\frac{n-1}{n^3+n^2+n+1} \approx 0.09465.</math>
| |||