Which function does NOT implement the Karnaugh map given below?

2000

Which function does NOT implement the Karnaugh map given below?

GATECS200034
  1. A.

    (w + x)y

  2. B.

    xy + yw

  3. C.

    (w + x)(w' + y)(x' + y)

  4. D.

    None of the above

Attempted by 28 students.

Show answer & explanation

Correct answer: D

Read the K-map using rows xy = 00, 01, 11, 10 and columns wz = 00, 01, 11, 10. The required 1-cells are the entire row xy = 11 and the two cells in row xy = 01 where w = 1. Therefore the function represented by the K-map is y(x + w).

Option A: (w + x)y = y(w + x), so it implements the map.
Option B: xy + yw = y(x + w), so it also implements the map.
Option C: (w + x)(w' + y)(x' + y). Since (w' + y)(x' + y) = y + w'x', this becomes (w + x)(y + w'x') = y(w + x). The second term is zero because (w + x)w'x' = 0. Hence option C also implements the same map.

Thus A, B, and C all implement the Karnaugh map. The function that does NOT implement it is none of them, so the correct option is D: None of the above.

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