CUET Preparation Today
If $A$ is a square matrix and $I$ is an identity matrix such that $A^2=A$, then $A(I-2 A)^3+2 A^3$ is equal to: |
$I+A$ $I+2 A$ $I-A$ -7A |
-7A |
The correct answer is Option (4) → -7A $A(I-2 A)^3+2 A^3$ $A(I^3-8A^3-6A+4A^2)+2A^3$ so $A^n=A$ $=A-8A-6A+4A+2A$ $=-7A$ |
