  The four exactly-solvable models related to non-sinusoidal coordinates,
namely, the Coulomb, Eckart, Rosen-Morse type I and II models are normally
being treated separately, despite the similarity of the functional forms of the
potentials, their eigenvalues and eigenfunctions. Based on an extension of the
prepotential approach to exactly and quasi-exactly solvable models proposed
previously, we show how these models can be derived and solved in a simple and
unified way.
