function fx = p52_fun ( n, x ) %*****************************************************************************80 % %% P52_FUN evaluates the integrand for problem 52. % % Discussion: % % The function has a singularity at x = 0. % % Interval: % % -1 <= x <= 5 % % Integrand: % % 1 / ( x * ( 5 * x^3 + 6 ) ) % % Exact Integral: % % ln ( 125 / 631 ) / 18 = -0.08994401... % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 12 November 2009 % % Author: % % John Burkardt % % Reference: % % Robert Piessens, Elise de Doncker-Kapenga, % Christian Ueberhuber, David Kahaner, % QUADPACK: A Subroutine Package for Automatic Integration, % Springer, 1983, page 109. % % Parameters: % % Input, integer N, the number of evaluation points. % % Input, real X(N), the evaluation points. % % Output, real FX(N), the integrand values. % fx(1:n) = x(1:n) .* ( 5.0 * x(1:n).^3 + 6.0 ); i = ( fx == 0.0 ); fx = 1.0 ./ fx; fx(i) = 0.0; return end