# How do you find E^-1 given E=((2, -2), (-1, 2)) ?

I found: $\left(\begin{matrix}1 & 1 \\ \frac{1}{2} & 1\end{matrix}\right) :$
You can check it by doing $E \cdot {E}^{-} 1$ to see if it is equal to the identity $\left(\begin{matrix}1 & 0 \\ 0 & 1\end{matrix}\right)$