Anyone who has taken a first-year quantum mechanics course has learned about the WKB ( Wentzel - Kramers - Brillouin ) method for approximating the energy levels of quantum mechanics systems and has learned that it gives the exact result for the simple harmonic oscillator. Using Mathematica it's easy to show that the approximation is fairly accurate for symmetric power law potentials in general, even for the ground state, as I discuss in
Accuracy of the Wentzel-Kramers-Brillouin ( WKB ) Quantization Condition for Symmetric Power Law Potentials
