JEE PYQ: Mathematical Reasoning Question 5
Question 5 - 2021 (24 Feb Shift 1)
The statement among the following that is a tautology is:
(1) $A \wedge (A \vee B)$
(2) $B \to [A \wedge (A \to B)]$
(3) $A \vee (A \wedge B)$
(4) $[A \wedge (A \to B)] \to B$
Type: MCQ
Show Answer
Answer: (4)
Solution
$A \wedge (\sim A \vee B) \to B = [(A \wedge \sim A) \vee (A \wedge B)] \to B = (A \wedge B) \to B = \sim A \vee \sim B \vee B = \sim A \vee t = t$ (tautology)
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