Chapter 8, Problem 54RE

Use symbolic notation, shown below, for the operations on an equilateral triangle.

$I=\left(\begin{array}{ccc}1& 2& 3\\ 1& 2& 3\end{array}\right)$, $R_{120}=\left(\begin{array}{ccc}1& 2& 3\\ 2& 3& 1\end{array}\right)$, $R_{240}=\left(\begin{array}{ccc}1& 2& 3\\ 3& 1& 2\end{array}\right)$ $R_l=\left(\begin{array}{ccc}1& 2& 3\\ 1& 3& 2\end{array}\right)$, $R_t=\left(\begin{array}{ccc}1& 2& 3\\ 3& 2& 1\end{array}\right)$, $R_r=\left(\begin{array}{ccc}1& 2& 3\\ 2& 1& 3\end{array}\right)$ $R_t\Delta R_r$