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Question: Answered & Verified by Expert
Which of the following statements is a tautology?
MathematicsMathematical ReasoningJEE MainJEE Main 2022 (25 Jul Shift 1)
Options:
  • A ~pqp
  • B p~pq
  • C ~pqq
  • D q~pq
Solution:
2043 Upvotes Verified Answer
The correct answer is: q~pq

Plotting the truth table of the following option we have,

p q ~p ~q ~pq
T T F F T
T F F T F
F T T F T
F F T T T

We know that, AB is only false when A is true and B is false, now using this rule and above table we will make truth table of options,

~pqp p~pq ~pqq q~pq
T T T T
T F T T
F T T T
F T F T

 

Hence q~pq is tautology.

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