POLYGAMMA _ _ _ _ _ _ _ _ _ _ _ _ operator

The Polygamma operator returns the Polygamma function.

Polygamma(n,x) := df(Psi(z),z,n);

syntax:

examples:

 Polygamma(1,2); 

     2
  (pi   - 6) / 6


on rounded; 

Polygamma(1,2.35); 

  0.52849689109

The Polygamma function is used for simplification of the ZETA function for some arguments.