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Ordinary Differential Equations

Section 4.4 The Laplace transform of linear systems

Some linear systems are easier to solve using the Laplace transform rather than eigenpair techniques. Here we take the Laplace transform of a set of linear differential equations and use algebraic techniques to solve for \(X(s)\) and \(Y(s)\text{.}\) We then use the inverse transform to find the \(x(t)\) and \(y(t)\) that satisfy our system.

Example 4.4.1.

Solve
\begin{equation*} \left\{ \begin{array}{ll} x'(t)-x(t)+y(t)=\mathcal{U}(t-2) \\ -x(t)+y'(t)+y(t)=0 \\ x(0)=y(0)=0. \end{array} \right. \end{equation*}

Example 4.4.2.

Solve
\begin{equation*} \left\{ \begin{array}{ll} x''(t)+3y'(t)+3y(t)=0 \\ x''(t)+3y(t)=e^{-t} \\ x(0)=x'(0)=y(0)=0 \end{array} \right. \end{equation*}