If $$D_{2n} = \{r^i s^j, \quad 0 ≤ i ≤ n − 1, \quad 0 ≤ j ≤ 1 \}$$ is the dihedral group of order $2n$, show that the center of $D_{2n}$, $n > 2$ is the trivial subgroup if $n$ is odd, and is the subgroup $\{e, r^{n/2} \}$ if $n$ is even.
I don't know how to proceed with this one.
Kindly help.
Thanks in advance.
