0007.ptx

<exercise masterit-seed="8476" masterit-slug="D4" masterit-name="Using Laplace transforms to solve IVPs">
  <statement>
    <p>
          Explain how to solve the following IVP.
      </p>
    <me> 18 \, \delta\left(t - 3\right) = -6 \, {y'} - 24 \, {y} + 3 \, {y''} \hspace{2em}
          y(0)= 0 ,
          y'(0)= -6 </me>
    <p>Hint: <m> \frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}} </m>.</p>
  </statement>
  <answer>
    <me>
          \mathcal{L}\{y\}= \frac{6 \, e^{\left(-3 \, s\right)}}{s^{2} - 2 \, s - 8} - \frac{6}{s^{2} - 2 \, s - 8} </me>
    <me>
          \mathcal{L}\{y\}= -\frac{e^{\left(-3 \, s\right)}}{s + 2} + \frac{e^{\left(-3 \, s\right)}}{s - 4} + \frac{1}{s + 2} - \frac{1}{s - 4} </me>
    <me> {y} = e^{\left(4 \, t - 12\right)} \mathrm{u}\left(t - 3\right) - e^{\left(-2 \, t + 6\right)} \mathrm{u}\left(t - 3\right) - e^{\left(4 \, t\right)} + e^{\left(-2 \, t\right)} </me>
  </answer>
</exercise>