Digamma

The digamma function , the logarithmic derivative of Gamma.

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Digamma(z)the digamma function .

Domain: Special functions

Details

Digamma is the order-zero polygamma: . The higher derivatives are PolyGamma.
, the negative Euler-Mascheroni constant.
Recurrence inherited from Gamma's functional equation: .
.
Poles at the nonpositive integers, the same poles as Gamma.
compute-engine reduces Digamma to a numeric value only via N() or an inexact argument; exact integer or rational arguments stay symbolic under plain evaluation except at the poles.

Examples

See also: Gamma, Zeta, GammaLn