Consider a Boolean expression given by 𝐹(𝑋, π‘Œ, 𝑍) = βˆ‘(3,5,6,7). Which of…

2024

Consider a Boolean expression given by 𝐹(𝑋, π‘Œ, 𝑍) = βˆ‘(3,5,6,7).

Which of the following statements is/are CORRECT?

  1. A.

    𝐹(𝑋, π‘Œ, 𝑍) = Ξ (0,1,2,4)

  2. B.

    𝐹(𝑋, π‘Œ, 𝑍) = π‘‹π‘Œ + π‘Œπ‘ +𝑋𝑍

  3. C.

    𝐹(𝑋, π‘Œ, 𝑍) is independent of inputΒ π‘Œ

  4. D.

    𝐹(𝑋, π‘Œ, 𝑍) is independent of input 𝑋

Attempted by 56 students.

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Correct answer: A, B

Solution:

Given F(X, Y, Z) = Ξ£(3,5,6,7).

  • Minterms where F = 1 are indices 3, 5, 6, 7 corresponding to binary inputs 011, 101, 110, 111.

  • Therefore the maxterms (where F = 0) are the remaining indices 0, 1, 2, 4, so F can be written as the product of maxterms Ξ (0,1,2,4).

Derive a simplified sum-of-products form from the minterms:

  1. Write the minterms: X' Y Z + X Y' Z + X Y Z' + X Y Z.

  2. Combine terms: X Y Z' + X Y Z = X Y (Z' + Z) = X Y.

  3. Also group the remaining terms with Z: X' Y Z + X Y' Z = Z (X' Y + X Y') = Z (X βŠ• Y) , and together with XY this yields the symmetric form XY + XZ + YZ.

Thus the simplified expression is F = XY + XZ + YZ.

Conclusion about the given statements:

  • The statement "F(X, Y, Z) = Ξ (0,1,2,4)" is correct because those indices are exactly where F = 0.

  • The statement "F(X, Y, Z) = XY + YZ + XZ" is correct; this is the simplified sum-of-products form.

  • The claims that F is independent of Y or independent of X are both incorrect. Counterexamples:

  • Dependence on Y: With X=1, Z=0, Y=0 gives input 100 (index 4) β†’ F=0, while Y=1 gives input 110 (index 6) β†’ F=1, so changing Y changes F.

  • Dependence on X: With Y=0, Z=1, X=0 gives input 001 (index 1) β†’ F=0, while X=1 gives input 101 (index 5) β†’ F=1, so changing X changes F.

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