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\begin{document}

\csection{Problem Set 5}

All of the following refer to angular momentum in three dimensions.

\begin{enumerate}
\item
Show that $[p_y ,~L_x ] = -i p_z$.
\item
Show that $[y,~L_x ] = -iz$.
\item
Show that $[p^2 , ~L^2 ] = 0$.
\item
Show that $[r^2 ,~ L^2 ] = 0$.
\item
Show that $L^2 = r^2 p^2 - ( \bold{r} \cdot \bold{p} )^2
 + i \bold{r} \cdot \bold{p}$.
\end{enumerate}

\end{document}
