If have proven that $\frac{O(2)}{SO(2)}$ is isomporphic to $\mathbb Z_2$.
Does is follow from this that $O(2)$ is isomorphic to $SO(2)\times\mathbb Z_2$
If have proven that $\frac{O(2)}{SO(2)}$ is isomporphic to $\mathbb Z_2$.
Does is follow from this that $O(2)$ is isomorphic to $SO(2)\times\mathbb Z_2$