Exercise 4 We recall that the Binomial coefficients are defined by (n ) n! k k!(n- k)! where n! = 1x 2x 3x . . . x n with the convention 0! = 1. Question 1 Prove the two following properties: ED EO Ea n n n+ 1 n n + S = k K - 1 = 1. k 0 n