CUET Preparation Today
Let A be a matrix such that $A^2=I$, where $I$ is an identity matrix, then $(I+A)^4-8A$ is equal to: |
$5I$ $8I$ $8(I+A)$ $5(I-A)$ |
$8I$ |
The correct answer is Option (2) → $8I$ $(I+A)^4-8A=I^A+4I^3A+6I^2A^2+4IA^3+A^4-8A$ $=(I+6I+I)+(4A+4A)-8A$ $=8I$ $[A^2=I]$ [Given] |
