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JEE Main 202229 JulyEvening Shift
Exam
JEE Main
Year
2022
Date
29 July
Shift
Evening Shift
Subject
Mathematics
Chapter
Mathematical Reasoning

JEE Main 2022 · 29 July · Evening Shift · Mathematics · Mathematical Reasoning

The statement (p ⇒ q) ∨ (p ⇒ r) is NOT equivalent to:

The statement (p⇒q)∨(p⇒r)isNOTequivalentto:\left(p ⇒ q\right) ∨ \left(p ⇒ r\right) is NOT equivalent to:

Options

  1. A(p∧( r))⇒q\left(p ∧ \left(~ r\right)\right) ⇒ q
  2. B( q)⇒(( r)∨p)\left(~ q\right) ⇒ \left(\left(~ r\right) ∨ p\right)
  3. Cp⇒(q∨r)p ⇒ \left(q ∨ r\right)
  4. D(p∧( q))⇒r\left(p ∧ \left(~ q\right)\right) ⇒ r

Correct answer

B. ( q)⇒(( r)∨p)\left(~ q\right) ⇒ \left(\left(~ r\right) ∨ p\right)

Step-by-step solution

Given,

(p⇒q)∨(p⇒r)</p><p>Nowusing\left(p ⇒ q\right) ∨ \left(p ⇒ r\right)</p><p>Now using the formula A ⇒ B ≡ ~ A ∨ B

We get, \left(~ p ∨ q\right)∨( p∨r)∨ \left(~ p ∨ r\right)

≡ p∨(q∨r)</p><p>≡ ~ p ∨ \left(q ∨ r\right)</p><p>≡ p ⇒ \left(q ∨ r\right),sooption, so optionCistrue.</p><p>Nowsolvingoptionis true.</p><p>Now solving option1weget,</p><p>(p∧ r)we get,</p><p> \left(p ∧ ~ r\right) ⇒ q</p><p></p><p>≡ ~ \left(p ∧ ~ r\right)∨q∨ q

≡( p∨r)≡ \left(~ p ∨ r\right) ∨ q</p><p></p><p>≡ ~ p ∨ \left(r ∨ q\right)</p><p></p><p>≡ \left(~ p ∨ r\right) ∨ \left(~ p ∨ q\right)

≡(p⇒q)≡ \left(p ⇒ q\right) ∨ \left(p ⇒ r\right),sooption, so option1isalsotrue,</p><p>Nowsolvingoptionis also true,</p><p>Now solving option4weget,</p><p>(p∧ q)we get, </p><p>\left(p ∧ ~ q\right) ⇒ r</p><p></p><p>≡ ~ \left(p ∧ ~ q\right)∨r∨ r

≡( p∨q)≡ \left(~ p ∨ q\right) ∨ r</p><p></p><p>≡ ~ p ∨ \left(q ∨ r\right)</p><p></p><p>≡ \left(~ p ∨ q\right) ∨ \left(~ p ∨ r\right)

≡(p⇒q)≡ \left(p ⇒ q\right) ∨ \left(p ⇒ r\right),sooption, so option4isalsocorrect.</p><p>Henceoptionis also correct.</p><p>Hence optionB is only wrong.

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