JEE Main 2020 — Mathematical Reasoning Question with Solution
From: JEE Main 2020 (Online) 2nd September Evening Slot
Question
Which of the following is a tautology ?
Choose an option
Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
~ p (p q) q
(~ p p) (~ p q) q
C (~ p q) q [C = contradiction]
(~ p q) q
~ (~ p q) q
(p ~ q) q
(p q) (~ q q)
(p q) t
so ~ p (p q) q is a tautology
(~ p p) (~ p q) q
C (~ p q) q [C = contradiction]
(~ p q) q
~ (~ p q) q
(p ~ q) q
(p q) (~ q q)
(p q) t
so ~ p (p q) q is a tautology
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