If P is a statement, then which of the following is a tautology?
2021
If P is a statement, then which of the following is a tautology?
Answer: C. P ∨ ¬P — A tautology is a statement that is always true. P ∨ ¬P is always true; this is the law of excluded middle . If P is true, then ¬P is false, so P ∨ ¬P is true.
- A.
P ∧ F
- B.
P ∨ F
- C.
P ∨ ¬P
- D.
P ∧ T
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Correct answer: C
A tautology is a statement that is always true. P ∨ ¬P is always true; this is the law of excluded middle . If P is true, then ¬P is false, so P ∨ ¬P is true.
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