“…When g(x) is smooth, numerical approaches such as collocation and Galerkin have been proposed and examined (see, for example, [2,3,8,10,20,22]); however the weighted L2 -convergence results presented are valid only if we assume that all the integrals involved in the numerical methods are evaluated exactly. The effect of numerical integration in the evaluation of the elements of the final linear system is still an open question.…”