Elements of order 2
Suppose
- Prove that an element in
has order dividing 2 if and only if it is its own inverse. - Prove that the number of elements in
of order 2 is odd. - Use (2) to show
must contain a subgroup of order 2.
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Suppose $G$ is a finite group of even order.
\begin{enumerate}[label=\alph*)]
\item Prove that an element in $G$ has order dividing 2 if and only if it is its own inverse.
\item Prove that the number of elements in $G$ of order 2 is odd.
\item Use (b) to show $G$ must contain a subgroup of order 2.
\end{enumerate}