# Symmetry Group of Regular Hexagon/Examples/Elements of Form beta alpha^k

## Examples of Operations on Symmetry Group of Regular Hexagon

Let $\HH = ABCDEF$ be a regular hexagon.

Let $D_6$ denote the symmetry group of $\HH$.

Let $e$ denote the identity mapping

Let $\alpha$ denote rotation of $\HH$ anticlockwise through $\dfrac \pi 3$ radians ($60 \degrees$)

Let $\beta$ denote reflection of $\HH$ in the $AD$ axis.

Consider elements of $D_6$ of the form $\beta \alpha^k$, for $k \in \Z^{\ge 0}$.

They can be expressed in the form:

$\beta \alpha^k = \alpha^{6 - k} \beta$

## Proof

$\beta \alpha^k = \alpha^{n - k} \beta$

for the dihedral group $D_n$.

The result follows by setting $n = 6$.

$\blacksquare$