Which of the following statement is a tautology?
- (A)
- (B)✓ Correct
- (C)
- (D)
Answer: (B)
Solution
Simplify by De Morgan's law to , so the statement becomes . Whenever the antecedent is true, is true, which makes true; and whenever the antecedent is false the implication is automatically true. Being true in every case, the statement is a tautology.
JEE Main · 2020 · 08 Jan 2020 · Shift 2 · Single correct option