COS 111, Fall 2000 - Problem Set 2

Solution set

Problems 1 through 3
From Brookshear, Chapter One Review Problems (pp. 73-74):
41 b, d, and f.

Problem 4 Give the truth table for the following logical expression

  not ((not x) or (not y))

Problem 5
The truth table below shows the value of the carry bit resulting from the addition of three input bits: x, y, and z. Write an expression (using AND, OR, and NOT), or, if you prefer, draw a circuit (using AND, OR, and NOT gates) to represent the carry bit function.

           x y z | carry(x,y,z)
          -------|-------------
           0 0 0 |    0
           0 1 0 |    0
           1 0 0 |    0
           1 1 0 |    1
           0 0 1 |    0
           0 1 1 |    1
           1 0 1 |    1
           1 1 1 |    1