function value = sincn_deriv ( x )

%*****************************************************************************80
%
%% sincn_deriv() evaluates the derivative of the normalized sinc() function.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    26 March 2025
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real x: the argument of the function.
%
%  Output:
%
%    real value: the value of the derivative.
%
  value = zeros ( size ( x ) );

  nz = find ( x ~= 0.0 );
  zr = find ( x == 0.0 );

  value(nz) = ( pi * x(nz) .* cos ( pi * x(nz) ) ...
    - sin ( pi * x(nz) ) ) ./ ( pi * x(nz).^2 );
  value(zr) = 0.0;

  return
end

