cs70_1

#cs70 A fundamental principle known as the law of the excluded middle says that, for any proposition P, either P is true or ¬P is true (but not both). Thus P ∨ ¬P is always true, regardless of the truth value of P. A propositional form that is always true regardless of the truth values of its variables is called a tautology. Conversely, a statement such as P∧ ¬P, which is always false, is called a contradiction

If we let P stand for the proposition “3 is odd”, Q stand for “4 is odd”, and R for “4+5 = 49”, what are the values of P∧R, P∨R and ¬Q? P∧R -> false P∨R -> True ¬Q -> True

Disjunction P Q P∨Q T T T T F T F T T F F F