Let p and q be two statements. Consider the following logical identities: (A)…

2024

Let p and q be two statements. Consider the following logical identities:
(A) ∼(p ∧ q) = ∼p ∨ ∼q
(B) ∼(p ∨ q) = ∼p ∧ ∼q
(C) p ∧ ∼p = T
(D) ∼(p → q) = p ∧ ∼q
(E) p ∨ q = ∼p ∨ ∼q
Choose the correct answer from the options given below:

Answer: A. (A), (B) and (D) OnlyCheck each statement: (A) ∼(p ∧ q) = ∼p ∨ ∼q This is De Morgan's law, so it is true. (B) ∼(p ∨ q) = ∼p ∧ ∼q This is also De Morgan's law, so it is true. (C) p…

  1. A.

    (A), (B) and (D) Only

  2. B.

    (D) Only

  3. C.

    (C), (D) and (E) Only

  4. D.

    (A), (B) and (C) Only

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Correct answer: A

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Check each statement:

(A) ∼(p ∧ q) = ∼p ∨ ∼q
This is De Morgan's law, so it is true.

(B) ∼(p ∨ q) = ∼p ∧ ∼q
This is also De Morgan's law, so it is true.

(C) p ∧ ∼p = T
A statement and its negation cannot both be true. Therefore p ∧ ∼p = F, not T. So (C) is false.

(D) ∼(p → q) = p ∧ ∼q
Since p → q ≡ ∼p ∨ q, we get:
∼(p → q) = ∼(∼p ∨ q) = p ∧ ∼q
So (D) is true.

(E) p ∨ q = ∼p ∨ ∼q
This is not a valid logical identity. For example, if p = T and q = T, then p ∨ q = T but ∼p ∨ ∼q = F. So (E) is false.

Therefore, the correct statements are (A), (B), and (D).

Final Answer: (A), (B) and (D) Only.

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