Question

Find the inverse of the matrices , if it exists.
$\left[\begin{array}{cc}2& 1\\ 4& 2\end{array}\right]$

Answer 1

Let $A=\left[\begin{array}{cc}2& 1\\ 4& 2\end{array}\right]$

$|A|=2\left(2\right)-4\left(1\right)=0$

$\Rightarrow A$ is a singular matrix.

Therefore, $A^{-1}$ does not exist.