Chapter 3.5, Problem 12P

In each of Problems 7 through $12$, find the solution of the given initial value problem. Draw the trajectory of the solution in the $x_1{x}_2-$ plane and also draw the component plots of $x_1$ versus $t$ and of $x_2$ versus $t$.

$X\text{'}=\left(\begin{array}{cc}2& \frac{1}{2}\\ -\frac{1}{2}& 1\end{array}\right)X,X\left(0\right)=\left(\begin{array}{l}1\\ 3\end{array}\right)$;