Q38 / 90 · JEE Main 2023 (25 Jan Shift 1) · Mathematics

The statement p∧~q⇒p⇒~q is

  • A
    equivalent to ~p∨~q
  • Correct answer
    B
    a tautology
  • C
    equivalent to p∨q
  • D
    a contradiction

Solution

Using logical equivalence condition p→q≡~p∨q, given statement can be expressed as, 

p∧~q→p→~q

≡ ~p∧~q∨~p∨~q.......(1)

We know De Morgan's law of logical equivalence is,

~p∧q≡~p∨~q

Applying De Morgan's law in equation(1) we get,

≡ ~p∨q∨~p∨~q   ∵~~p≡p

≡ ~p∨~p∨q∨~q

≡~p∨t≡t (tautology)

Hence, the correct answer is option: 'B'.

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