digamma function


h19digaf.gif (1521 bytes)

h19diga.gif (1878 bytes)The derivative of the logarithmic gamma function, the digamma function ψ(x) can be used to clarify the sum of some rational series.

The following relation can be used:

h19digag.gif (1225 bytes)

The digamma function can be generalized to the nth derivative as the polygamma function.