Exercise 1.4.4: Proving whether two logical expressions are equivalent. About Determine whether the following pairs of expressions are logically equivalent. Prove your answer. If the pair is logically equivalent, then use a truth table to prove your answer.

(a) (p q) and p q

(b) (p q) and p q

(c) p (p q) and p q

(d) p (p q) and p q