Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Matrices

Question:

If $A^3 =0$ such that $A^n≠ I$ for $1 ≤n≤4$, then $(I-A)^{-1}=?$

Options:

$A^4$

$A^3$

$I+A$

none of these

Correct Answer:

none of these

Explanation:

We have,

$A^4 (I-A) = A^4-A^5 = A^4-O = A^4 ≠I$

$A^3 (I-A) = A^3-A^4 ≠ I$

and, $(I + A) (I - A) = I-A^2 ≠ I$

Hence, $(I-A)^{-1} ≠A^4, A^3, I+A$.