<item ident="F4-5213" title="F4 | Implicit solutions for exact IVPs | ver. 5213"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>F4.</strong> </p> <p> Determine which of the following ODEs is exact. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}" alt="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}" title="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}" data-latex="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}"/> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" alt="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" title="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" data-latex="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y"/> </p> <p> Then find an implicit solution for this exact ODE satisfying the initial value <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y( 1 )= -1" alt="y( 1 )= -1" title="y( 1 )= -1" data-latex="y( 1 )= -1"/>. </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>F4.</strong> </p> <p> Determine which of the following ODEs is exact. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?6%20%5C,%20t%20y%5E%7B2%7D%20+%206%20%5C,%20t%20=%202%20%5C,%20t%5E%7B2%7D%20%7By'%7D%20-%202%20%5C,%20t%20y%20%7By'%7D%20-%202%20%5C,%20t%20%7By'%7D" alt="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}" title="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}" data-latex="6 \, t y^{2} + 6 \, t = 2 \, t^{2} {y'} - 2 \, t y {y'} - 2 \, t {y'}"> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-6%20%5C,%20t%20y%5E%7B2%7D%20-%206%20%5C,%20t%20=%206%20%5C,%20t%5E%7B2%7D%20y%20%7By'%7D%20+%202%20%5C,%20t%20%7By'%7D%20+%202%20%5C,%20y" alt="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" title="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" data-latex="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y"> </p> <p> Then find an implicit solution for this exact ODE satisfying the initial value <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y(%201%20)=%20-1" alt="y( 1 )= -1" title="y( 1 )= -1" data-latex="y( 1 )= -1">. </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>The following ODE is exact.</p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" alt="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" title="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" data-latex="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y"/> </p> <p> Its implicit solution satisfying the initial value is: </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)" alt="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)" title="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)" data-latex="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)"/> </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <p>The following ODE is exact.</p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-6%20%5C,%20t%20y%5E%7B2%7D%20-%206%20%5C,%20t%20=%206%20%5C,%20t%5E%7B2%7D%20y%20%7By'%7D%20+%202%20%5C,%20t%20%7By'%7D%20+%202%20%5C,%20y" alt="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" title="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y" data-latex="-6 \, t y^{2} - 6 \, t = 6 \, t^{2} y {y'} + 2 \, t {y'} + 2 \, y"> </p> <p> Its implicit solution satisfying the initial value is: </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-3%20%5C,%20t%5E%7B2%7D%20y%5E%7B2%7D%20-%203%20%5C,%20t%5E%7B2%7D%20-%202%20%5C,%20t%20y%20=%20%5Cleft(-4%5Cright)" alt="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)" title="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)" data-latex="-3 \, t^{2} y^{2} - 3 \, t^{2} - 2 \, t y = \left(-4\right)"> </p> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>