<item ident="F4-2307" title="F4 | Implicit solutions for exact IVPs | ver. 2307"> <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?-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" alt="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" title="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" data-latex="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - 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?-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{2} - y" alt="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{2} - y" title="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{2} - y" data-latex="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{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?-9%20%5C,%20y%5E%7B2%7D%20%7By'%7D%20-%2012%20%5C,%20t%5E%7B2%7D%20=%20-t%20%7By'%7D%20-%20y" alt="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" title="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" data-latex="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - 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?-9%20%5C,%20y%5E%7B2%7D%20%7By'%7D%20=%204%20%5C,%20t%20y%5E%7B2%7D%20+%20t%5E%7B2%7D%20%7By'%7D%20+%206%20%5C,%20t%20y%20%7By'%7D%20+%2012%20%5C,%20t%5E%7B2%7D%20-%20y" alt="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{2} - y" title="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{2} - y" data-latex="-9 \, y^{2} {y'} = 4 \, t y^{2} + t^{2} {y'} + 6 \, t y {y'} + 12 \, t^{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?-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" alt="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" title="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" data-latex="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - 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?-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)" alt="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)" title="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)" data-latex="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\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?-9%20%5C,%20y%5E%7B2%7D%20%7By'%7D%20-%2012%20%5C,%20t%5E%7B2%7D%20=%20-t%20%7By'%7D%20-%20y" alt="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" title="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - y" data-latex="-9 \, y^{2} {y'} - 12 \, t^{2} = -t {y'} - 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?-4%20%5C,%20t%5E%7B3%7D%20-%203%20%5C,%20y%5E%7B3%7D%20+%20t%20y%20=%20%5Cleft(-2%5Cright)" alt="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)" title="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)" data-latex="-4 \, t^{3} - 3 \, y^{3} + t y = \left(-2\right)"> </p> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>