Elements of order 2

Mar 18, 2025 5:52 PM

Suppose G is a finite group of even order.

  1. Prove that an element in G has order dividing 2 if and only if it is its own inverse.
  2. Prove that the number of elements in G of order 2 is odd.
  3. Use (2) to show G must contain a subgroup of order 2.