Exercise 1: Express the following in summation notation. (a) 1 + 20400 8, 000+.... Express the following in summation notation and use induction to prove for n (a natural number) 1. 1+3+5+ (2n-1) n2 1.3 3.5 5.7 n 2 2, then n3-n is always divisible by 3 (2n-1)(2n+1) 2n+1 3. Exercise 2: For each of the binary relations described below Write the pairs that satisfy this relation. What properties does this relation have? (reflexive, symmetric, anti-symmetric, transitive) a) y x+1 on the set S (1, 2,3, 4,5) b) y s x on the set S (0, 2,3,8, 9) c) y is multiple of x on the set S (1,3, 4,6,8,9, 12)