Question

The matrix \( A = \begin{pmatrix} 1 & 2 \\ 3 & 1 \end{pmatrix} \), then adj \( (A) \) is equal to

• A. \( \begin{pmatrix} 1 & 2 \\ 3 & 1 \end{pmatrix} \)
• B. \( \begin{pmatrix} 2 & -3 \\ -1 & 1 \end{pmatrix} \)
• C. \( \begin{pmatrix} -3 & 1 \\ 2 & 1 \end{pmatrix} \)
• D. None of these

Hint:

The adjoint of a matrix is found by taking the cofactor matrix and transposing it.

Answer 1

The Correct Option is B

To find the adjoint of matrix \( A \), we calculate the cofactor matrix and then transpose it.