Transforming A reas Fo $r$ Problems 49-52, let $T: \mathbb{R}^2 \rightarrow \mathbb{R}^2$ be defined by $T(\overrightarrow{\mathbf{v}})=\mathbf{A} \overrightarrow{\mathbf{v}}$, where
$$
A=\left[\begin{array}{rr}
1 & -1 \\
2 & 1
\end{array}\right] .
$$
Calculate the determinant $|\mathbf{A}|$. Can you guess a connection with the results of Problems 49-51? What additional data might you collect?