Question

Which of the following is not equal to $1$ in Boolean algebra ?

• A. $\overline{A.\bar{A}}$
• B. $A.\bar{A}$
• C. $A+\bar{A}$
• D. $A+1$

Answer 1

Answer: (B)

$\overline{A.\bar{A}}=\bar{A}+\overline{\stackrel{ˉ}{A}}=\bar{A}+A=1$
$A\cdot \bar{A}=0$
$A+\bar{A}=1$
$A+1=1$