function Z = zeta(n,X)
%ZETA   Symbolic Riemann zeta function.
%   ZETA(z) = sum(1/k^z,k,1,inf).
%   ZETA(n,z) = n-th derivative of ZETA(z)

%   Copyright (c) 1993-1999 The Mathworks, Inc. All Rights Reserved.
%   $Revision: 1.7 $  $Date: 1999/01/05 13:58:07 $

if nargin == 1
   Z = double(zeta(sym(n)));
else
   Z = double(zeta(sym(n),sym(X)));
end
