4) Proof by contradiction Suppose we know the shortest path from A to D is A to B to C to D. Using the technique of proof by contradiction, show why the shortest path from A to C must be A to B to C. 5) Induction proofs. a. Prove by induction: n sum (2i-1) = n^2 i=1 Note: sum is intended to be the summation symbol, and ^ means what follows is an exponent 6) Given: T(1) = 3 T(N) = T(N-1) + 3, N>1 What would the value of T(10) be?