Let \(A=\left[\begin{array}{ll}2 & 1 \\ 1 & 2\end{array}\right]\). Then A-1 is given by :
1
\(\left[\begin{array}{ll}\frac{2}{8} & \frac{1}{4} \\ \frac{1}{8} & \frac{1}{4}\end{array}\right]\)
2
\(\left[\begin{array}{cc}\frac{2}{4} & \frac{-1}{4} \\ \frac{-1}{4} & \frac{2}{4}\end{array}\right]\)
3
\(\left[\begin{array}{ll}\frac{2}{4} & \frac{2}{4} \\ \frac{1}{4} & \frac{1}{4}\end{array}\right]\)
4
\(\left[\begin{array}{cc}\frac{2}{4} & \frac{2}{4} \\ \frac{-1}{4} & \frac{-1}{4}\end{array}\right] \)