Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Algebra

Question:

If matrix $A=[aij]_{2×2}$ where $aij=\left\{\begin{matrix} 1, i≠j\\0, i=j\end{matrix}\right.$,then $A^3$ is equal to :

Options:

2I

O

I

$A^T$

Correct Answer:

$A^T$

Explanation:

$a_{ij}=1 \text{ for } i\ne j,\; a_{ij}=0 \text{ for } i=j.$

$A=\begin{bmatrix}0&1\\1&0\end{bmatrix}.$

$A^2=\begin{bmatrix}1&0\\0&1\end{bmatrix}=I.$

$A^3=A^2A=IA=A.$

$A^T=A.$

$A^3=A^T.$