Question

For two matrices A and B of same order, if AB = A and BA = B then $A^2$is equal to?

• A. I (identity matrix)
• B. A
• C. B
• D. $\varphi \left(nullmatix\right)$

Answer 1

The correct option is B A

$A^2=A.A=\mathrm{AB}.A(\because A=\mathrm{AB})=A.B(\because \mathrm{BA}=B)=A(\because \mathrm{AB}=A)\mathrm{option}\left(b\right)\mathrm{is}\mathrm{correct}$