Inverse of Group Product/Proof 1

Proof
The result follows from Group Product Identity therefore Inverses:


 * $\paren {a \circ b} \circ \paren {b^{-1} \circ a^{-1} } = e \implies \paren {a \circ b}^{-1} = b^{-1} \circ a^{-1}$