Which expression represents De Morgan's Law for the complement of a product?

2025

Which expression represents De Morgan's Law for the complement of a product?

  1. A.

    (A + B)' = A' · B'

  2. B.

    (A · B)' = A' + B'

  3. C.

    (A · B)' = A' + B

  4. D.

    (A · B)' = A + B'

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Correct answer: B

For the complement of a product, De Morgan's Law is:

(A · B)' = A' + B'

This means NOT (A AND B) is equivalent to (NOT A) OR (NOT B).

The related De Morgan identity for the complement of a sum is:

(A + B)' = A' · B'

That identity is true, but it is not the product-complement form asked in this question.

Correct option: B

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