function value = fd ( f, x, h )

%*****************************************************************************80
%
%% fd computes a forward difference estimate of the first derivative.
%
%  Discussion:
%
%    x can be a vector, so that you can create a plot of the forward difference.
%
%    h can be a vector, so you can compare the estimate for various values of h.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    31 August 2019
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    function handle, f, evaluates the function.
%
%    real x, the point at which the derivative is to be estimated.
%
%    real h, the stepsize to use.
%
%  Output:
%
%    real value, the forward difference estimate.
%
  value = ( f ( x + h ) - f ( x ) ) ./ h;

  return
end

