Chapter 41.1, Problem 41.1TYU

To determine

The conclusion about $\phi \left(x,y,z\right)$ in region where ${\partial }^2\phi /\partial x^2>0$, ${\partial }^2\phi /\partial y^2>0$, ${\partial }^2\phi /\partial z^2>0$ and value of definite energy is positive and the potential energy function is zero.