function f = p13_f ( x )

%*****************************************************************************80
%
%% p13_f() evaluates the objective function for test 13.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    16 March 2026
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real x: the argument.
%
%  Output:
%
%    real f: the function value.
%
  f = 100.0 + ( 1.0 - exp ( x ) .* sin ( x ) ).^2;

  return
end

