function y = fprunge ( x ) %*****************************************************************************80 % %% FPRUNGE evaluates the derivative of the Runge function. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 23 February 2004 % % Author: % % John Burkardt % % Parameters: % % Input, real X, the argument. % % Output, real FPRUNGE, the value of the derivative of the Runge function. % y = -50.0E+00 * x ./ ( 1.0E+00 + 25.0E+00 * x.^2 ) .^2; return end