Exercise 1: Proving the Commutative Law for AND — Possible Solution ==================================================================== GIVEN ------------------------------ Prove xy = yx for all values of x and y, using a full truth table. TRUTH TABLE, ALL 4 COMBINATIONS ------------------------------ x=0, y=0: xy = 0.0 = 0. yx = 0.0 = 0. Match. x=0, y=1: xy = 0.1 = 0. yx = 1.0 = 0. Match. x=1, y=0: xy = 1.0 = 0. yx = 0.1 = 0. Match. x=1, y=1: xy = 1.1 = 1. yx = 1.1 = 1. Match. RESULT ------------------------------ xy and yx produce identical results across all 4 possible input combinations - since these are the only inputs a Boolean variable pair can ever take, this is a complete proof, not just supporting evidence. The commutative law xy = yx holds. WHY THIS WORKS AS AN ANSWER ------------------------------ All 4 combinations are checked explicitly rather than a representative sample, matching this chapter's own stated proof method - since there are only 4 possible (x,y) pairs total, checking all of them genuinely does prove the law completely, not just make it likely.