In: Advanced Math
Number Theory Course
1. Let ? and ? be integers. Show that if ? + ? is odd, then ?
and ? are of the opposite parity:
a. By giving a proof by contradiction
2. Let n be a natural number. Prove that (?+ 1)2 −1 is even if and
only if n is even. You may use any suitable proof technique.
3. Using a proof by induction, show that 5 | 6? − 1, for all
natural numbers ? .