  It is shown that the eigenvalue problem for the Hamiltonians of the standard
form, $H=p^2/(2m)+V(x)$, is equivalent to the classical dynamical equation for
certain harmonic oscillators with time-dependent frequency. This is another
indication of the central role played by time-dependent harmonic oscillators in
quantum mechanics. The utility of the known results for eigenvalue problem in
the solution of the dynamical equations of a class of time-dependent harmonic
oscillators is also pointed out.
