Recently was introduced in the literature a procedure to obtain ansatze, free of parameters, for the eigenfunctions of the time-independent Schrodinger equation with symmetric convex potential. In the present work, we test this technique in regard to $x^{2kappa}$-type potentials. We study the behavior of the ansatze regarding the degree of the potential and to the intervening coupling constant. Finally, we discuss how the results could be used to establish the upper bounds of the relative errors in situations where intervening polynomial potentials.