# Tag Info

The lower limit should be negative: $$\int_{\color{red}-\sqrt{2E/k}}^0 \sqrt{2m\left(E-\frac{1}{2}kx^2\right)} dx + \int _0^{E/mg} \sqrt{2m(E-mgx)} dx =\left(n-\frac{1}{2}\right) \pi \hbar$$ but the answer is yes: this is the correct expression. The general expression for the WKB approximation is  \int_{x^1}^{x^2}\sqrt{2m(E-V(x))} ...