From this equation, q 2 is a factor of 2. If q 2 is a factor of 2, then q is also a factor of 2 (this part of the proof is a little tricky). We can thus write,
From this equation, q2is a factor of 2. If q2is a factor of 2, then q is alsoa factor of 2 (this part of the proof is a little tricky). We can thus write,