Question: 1. Decide whether or not it is true that (A×B)∪(C×D)=(A∪C)×(B∪D). If true, give a proof. If false, give a counterexample.
2. Show that if A and B are sets, then if A\B = 0, then / B = 0 (unless / A = 0).
3. Suppose R is false but that (P ⇒ Q) ⇔ (R ∧ S) is true. Is P true or false? What about Q?
4. Could we rewrite the conditional ((c > 5 && b == a) || c >= 5) in a simpler way? If so, what is it? (Suggestion: use a truth table.)