  Recently developed simple approach for the exact/approximate solution of
Schrodinger equations with constant/position-dependent mass, in which the
potential is considered as in the perturbation theory, is shown to be
equivalent to the one leading to the construction of exactly solvable
potentials via the solution of second-order differential equations in terms of
known special functions. The formalism in the former solves difficulties
encountered in the latter in revealing the corrections explicitly to the
unperturbed piece of the solutions whereas the other obviate cumbersome
procedures used in the calculations of the former.
