Question

Which best describes the given compound propositions [p ∧ (q v r)] <-> [(p ∧ q) v (p ∧ r)]

Answer 1

Taking into account that $\alpha\leftrightarrow\alpha\equiv T$ for any formula $\alpha$ and

$[p ∧ (q \lor r)] \leftrightarrow [(p ∧ q) \lor (p ∧ r)]\equiv [p ∧ (q \lor r)] \leftrightarrow [p ∧ (q \lor r)] \equiv T,$

we conclude that this formula is tautology and the logic constant $T$ the best describes the given compound proposition.