function f = p23_f ( x )

%*****************************************************************************80
%
%% p23_f() evaluates the objective function for test 23.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    23 February 2026
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real x: the argument.
%
%  Output:
%
%    real f: the function value.
%
  f = 1.2 + log ( x ) .* cos ( 2.0 * ( 4.0 - x ) );

  return
end

