function y = ftest3(x)
    % This is a test function for Simpson's rule using (local) subfunctions
    y = x.^2 + sfun(x,1) + sfun(x,2) + sfun(x,3);
    
    function y = sfun(x,p)
        % This is a subfunction accessible only to ftest3
        y = x.^p.*exp(-x.^p);