Question

$\begin{array}{c}AdjointofthematrixN\left[\begin{array}{ccc}-4& -3& -3\\ 1& 0& 1\\ 4& 4& 3\end{array}\right]\end{array}$ is [MP PET 1989]

• A. N
• B. 2N
• C. -N
• D. None of these

Answer 1

The correct option is A

N

$\begin{array}{c}CofactorsofthematrixN=\left[\begin{array}{ccc}-4& -3& -3\\ 1& 0& 1\\ 4& 4& 3\end{array}\right]are{c}_{11}=-4,c_{12}=1,c_{13}=4;c_{21}=-3,c_{22}=0,c_{23}=4;c_{31}=-3,c_{32}=1,c_{33}=3\end{array}$

$\begin{array}{c}adjN=\left[\begin{array}{ccc}-4& -3& -3\\ 1& 0& 1\\ 4& 4& 3\end{array}\right]=N\end{array}$