How to prove abelian group I am struggling answering this question for myself:
How can i prove that a Group $G$ is abelian, if $$g\circ g=e \ \forall g \in G $$
A group is abelian if this is true:
$$a\circ b = b\circ a\ \forall a,b \in G$$
But i dont understand how to prove this.
Hope someone can help me out with this!

Note that $g=g^{-1}$ for any $g$. So, $(ab)^2=abab=e$ and thus $ab=b^{-1}a^{-1} = ba$ for all $a,b \in G$.
