Chapter 10, Problem 10.82E

What are $\langle x\rangle ,\langle y\rangle ,$ and $\langle z\rangle$ for ${\Psi }_{111}$ of a $\text{3-D}$ particle-in-a-box? (The operators for $y$ and $z$ are similar to the operator for $x$, except that $y$ is substituted for $x$ wherever it appears, and the same for $z$.) What point in the box is described by these average values?