Exercise

1. Solve the following differential equations.
\begin{displaymath}\begin{array}{ll}
(a) \ \left\{\begin{array}{l}
x_{1}^{\prime...
...n{array}{c}
t^{2}\\
0\\
0\\
0
\end{array}\right)
\end{array}\end{displaymath}
2. Solve the differential equation by using the system of differential equation.
\begin{displaymath}\begin{array}{l}
\ y^{\prime\prime} + 4y^{\prime} + 3y = t
\end{array}\end{displaymath}
3. Solve by elimination.
\begin{displaymath}\begin{array}{ll}
(a) \ \left\{\begin{array}{rl}
x_{1}^{\prim...
...ime} - 3x_{1} + x_{2} &= 2t - 1
\end{array}\right .
\end{array}\end{displaymath}