Order of an element in a finite group

Let $G$ be a finite group. Prove from the definitions that there exists a number $N$ such that $a^{N} = e$ for all $a \in G$ .

View

L A T E X

code

Let $G$ be a finite group. Prove {\itshape from the definitions} that there exists a number $N$ such that $a^N=e$ for all $a\in G$.