Let A be a matrix such that $A^2=I$, where $I$ is an identity matrix, then $(I+A)^4-8A$ is equal to:
Answer & explanation
Correct answer: option 2
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]