<item ident="D4-8248" title="D4 | Using Laplace transforms to solve IVPs | ver. 8248"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>D4.</strong> </p> <p> Explain how to solve the following IVP. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12" alt="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12" title="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12" data-latex="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12"/> </p> <p>Hint: <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}" alt="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}" title="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}" data-latex="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}"/>.</p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>D4.</strong> </p> <p> Explain how to solve the following IVP. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?4%20%5C,%20%7By'%7D%20+%2016%20%5C,%20%7By%7D%20=%202%20%5C,%20%7By''%7D%20-%2012%20%5C,%20%5Cdelta%5Cleft(t%20-%202%5Cright)%20%5Chspace%7B2em%7D%20y(0)=%200%20,%20y'(0)=%2012" alt="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12" title="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12" data-latex="4 \, {y'} + 16 \, {y} = 2 \, {y''} - 12 \, \delta\left(t - 2\right) \hspace{2em} y(0)= 0 , y'(0)= 12"> </p> <p>Hint: <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cfrac%7B1%7D%7Bs%5E%7B2%7D%20-%202%20%5C,%20s%20-%208%7D%20=%20-%5Cfrac%7B1%7D%7B6%20%5C,%20%7B%5Cleft(s%20+%202%5Cright)%7D%7D%20+%20%5Cfrac%7B1%7D%7B6%20%5C,%20%7B%5Cleft(s%20-%204%5Cright)%7D%7D" alt="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}" title="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}" data-latex="\frac{1}{s^{2} - 2 \, s - 8} = -\frac{1}{6 \, {\left(s + 2\right)}} + \frac{1}{6 \, {\left(s - 4\right)}}">.</p> </div> </mattext> </material> <response_str ident="response1" rcardinality="Single"> <render_fib> <response_label ident="answer1" rshuffle="No"/> </render_fib> </response_str> </presentation> <itemfeedback ident="general_fb"> <flow_mat> <material> <mattextxml> <div class="exercise-answer"> <h4>Partial Answer:</h4> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}" alt="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}" title="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}" data-latex="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}"/> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}" alt="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}" title="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}" data-latex="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}"/> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}" alt="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}" title="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}" data-latex="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}"/> </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cmathcal%7BL%7D%5C%7By%5C%7D=%20%5Cfrac%7B6%20%5C,%20e%5E%7B%5Cleft(-2%20%5C,%20s%5Cright)%7D%7D%7Bs%5E%7B2%7D%20-%202%20%5C,%20s%20-%208%7D%20+%20%5Cfrac%7B12%7D%7Bs%5E%7B2%7D%20-%202%20%5C,%20s%20-%208%7D" alt="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}" title="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}" data-latex="\mathcal{L}\{y\}= \frac{6 \, e^{\left(-2 \, s\right)}}{s^{2} - 2 \, s - 8} + \frac{12}{s^{2} - 2 \, s - 8}"> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cmathcal%7BL%7D%5C%7By%5C%7D=%20-%5Cfrac%7Be%5E%7B%5Cleft(-2%20%5C,%20s%5Cright)%7D%7D%7Bs%20+%202%7D%20+%20%5Cfrac%7Be%5E%7B%5Cleft(-2%20%5C,%20s%5Cright)%7D%7D%7Bs%20-%204%7D%20-%20%5Cfrac%7B2%7D%7Bs%20+%202%7D%20+%20%5Cfrac%7B2%7D%7Bs%20-%204%7D" alt="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}" title="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}" data-latex="\mathcal{L}\{y\}= -\frac{e^{\left(-2 \, s\right)}}{s + 2} + \frac{e^{\left(-2 \, s\right)}}{s - 4} - \frac{2}{s + 2} + \frac{2}{s - 4}"> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%7By%7D%20=%20e%5E%7B%5Cleft(4%20%5C,%20t%20-%208%5Cright)%7D%20%5Cmathrm%7Bu%7D%5Cleft(t%20-%202%5Cright)%20-%20e%5E%7B%5Cleft(-2%20%5C,%20t%20+%204%5Cright)%7D%20%5Cmathrm%7Bu%7D%5Cleft(t%20-%202%5Cright)%20+%202%20%5C,%20e%5E%7B%5Cleft(4%20%5C,%20t%5Cright)%7D%20-%202%20%5C,%20e%5E%7B%5Cleft(-2%20%5C,%20t%5Cright)%7D" alt="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}" title="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}" data-latex="{y} = e^{\left(4 \, t - 8\right)} \mathrm{u}\left(t - 2\right) - e^{\left(-2 \, t + 4\right)} \mathrm{u}\left(t - 2\right) + 2 \, e^{\left(4 \, t\right)} - 2 \, e^{\left(-2 \, t\right)}"> </p> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>