  Standard power series are used to construct and analyze angular and radial
spheroidal functions, which are necessary for solving boundary value problems
for Helmholtz equation in a spheroid. With an advanced approach the low-lying
energy levels of a deep spheroidal quantum well are calculated as a function of
the spheroid semiaxes ratio a/b. The well-known results for cylindrical and
spherical wells are reproduced in the limits a/b >> 1, and a/b ~ 1,
respectively.
