Find a d j A for A= [ ll 2 & 3 1 & 4 ] - Vidyadip

MCQ

Find $\mathrm{a d j}$ $\mathrm{A}$ for $\mathrm{A}=\left[\begin{array}{ll}2 & 3 \\ 1 & 4\end{array}\right]$

A
$\left[\begin{array}{cc}4 & 3 \\ -1 & 2\end{array}\right]$
B
$\left[\begin{array}{cc}-4 & -3 \\ -1 & 2\end{array}\right]$
✓
$\left[\begin{array}{cc}4 & -3 \\ -1 & 2\end{array}\right]$
D
$\left[\begin{array}{cc}4 & -3 \\ 1 & 2\end{array}\right]$

✓

Answer

Correct option: C.

$\left[\begin{array}{cc}4 & -3 \\ -1 & 2\end{array}\right]$

c
Solution We have $A_{11}=4, A_{12}=-1, A_{21}=-3, A_{22}=2$

Hence,

$adj$ $\mathrm{A}=\left[\begin{array}{ll}\mathrm{A}_{11} & \mathrm{A}_{21} \\ \mathrm{A}_{12} & \mathrm{A}_{22}\end{array}\right]=\left[\begin{array}{cc}4 & -3 \\ -1 & 2\end{array}\right]$

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