Question

The value of $(\overline{A}+\overline{B})\times (\overline{A}-\overline{B})$ is

• A. $0$
• B. $A^2-B^2$
• C. $\overline{B}\times \overline{A}$
• D. $2(\overline{B}\times \overline{A})$

Answer 1

The correct option is D $2(\overline{B}\times \overline{A})$

$(\overrightarrow{A}+\overrightarrow{B})\times (\overrightarrow{A}-\overrightarrow{B})=\overrightarrow{A}\times \overrightarrow{A}-\overrightarrow{A}\times \overrightarrow{B}+\overrightarrow{B}\times \overrightarrow{A}-\overrightarrow{B}\times \overrightarrow{B}=2(\overrightarrow{B}\times \overrightarrow{A})$