33. AB

35. The truth table below represents a circuit which will be

Solution:

encountered in digital computers. Notice, there are three

A 1 output occurs

binary variables, A, B, and K. The possible truth

in the CARRY

column when A is

1 and B is 1;

thus, the Boolean

A

B

K

SUM

CARRY

product for this

0

0

0

0

0

condition is AB.

0

0

1

1

0

0

1

0

1

0

0

1

1

0

1

1

0

0

1

0

1

0

1

0

1

1

1

0

0

1

1

1

1

1

1

34.

To derive a minterm expression for the SUM-output column,

first write the Boolean product for each output which is a 1

a. X(X+Y) =X

in the SUM column. After the Boolean product is written for

1

each 1 output, the outputs are ORed together to form a

1

1

minterm expression. The SUM-output minterm expression

1

b. Yes.

derived from the truth table above is

ABK + ABK + ABK + ABK

Derive the minterm expression from the CARRY output of

the truth table above.