Use truth tables to show that the following pairs of expressions are logically equivalent. a. p harr q and (p rightarrow q) and (q rightarrow p) b. p rightarrow q and p or q Below are the steps of a proof showing that two logical expressions are logically equivalent. Label each of the steps below with the law of propositional logic used. (The first step, i, doesn't need a "law" label, as it's just our starting point.) i. (p rightarrow q) and (p or q) Starting point ii. ( p or q) and (p or q) iii. ( p and p) or q iv. F or