Exact WKB expansions for some potentials

We find WKB expansions for the spectra of the three-dimensional isotropic h armonic oscillator and Eckart and Morse potentials. It is shown that for al l these potentials the series are convergent and, when summed, yield the ex act energy spectra. These results support our working hypothesis that the W KB series for the energy spectra are convergent for all one-dimensional sol vable potentials and their sums yield the exact energies.