Chapter 2, Problem 45E

In the dihedral group $D_n$ , let $R=R_{360/n}$ and let F be any reflection.Write each of the following products in the form $R^i\text{or}{R}^{i}F$, where $0\le i\le n$ .
a. In $D_4,F{R}^{-2}F{R}^5$
b. In $D_5,R^{-3}F{R}^{4}F{R}^{-2}$
c. In $D_6,F{R}^{5}F{R}^{-2}F$