2. The ground state (apart from normalization) of a particle of unit mass moving in a one-dimensional potential $V(x)$ is $\exp(-x^2/2)\cosh(\sqrt{2}x)$. The potential $V(x)$, in suitable units so that $\hbar=1$, is (up to an additive constant).
(a) $\pi^2/2$
(b) $\frac{\pi^2}{2} - \sqrt{2}x \tanh(\sqrt{2}x)$
(c) $\frac{\pi^2}{2} - \sqrt{2}x \tan(\sqrt{2}x)$
(d) $\frac{\pi^2}{2} - \sqrt{2}x \coth(\sqrt{2}x)$