Question

Which of the following Boolean rules is correct?
1. A + 0 = 0
2. A + 1 = 1
3. \(\overline {A + A} = \overline {A.A}\)
4. \(A + A.B = \overline {A+B}\)

Answer 1

Correct Answer - Option 2 : A + 1 = 1

Concept:

All Boolean algebra laws are shown below

Name	AND Form	OR Form
Identity law	1.A = A	0 + A = A
Null Law	0.A = 0	1 + A = 1
Idempotent Law	A. A = A	A + A = A
Inverse Law	AA’ = 0	A + A’ = 1
Commutative Law	AB = BA	A + B = B + A
Associative Law	(AB)C	(A + B) + C = A + (B + C)
Distributive Law	A + BC = (A + B) (A + C)	A (B + C) = AB + AC
Absorption Law	A (A + B) = A	A + AB = A
De Morgan’s Law	(AB)’ = A’ + B’	(A + B)’ = A’B’