<item ident="F4-0849" title="F4 | Implicit solutions for exact IVPs | ver. 0849">
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<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?16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t" alt="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t" title="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t" data-latex="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t"/>
</p>
<p style="text-align:center;">
<img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" alt="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" title="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" data-latex="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t 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>
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<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?16%20%5C,%20y%5E%7B3%7D%20%7By'%7D%20+%202%20%5C,%20t%20y%20%7By'%7D%20-%208%20%5C,%20t%20y%20-%205%20%5C,%20t%20%7By'%7D%20=%2010%20%5C,%20t%20y%5E%7B2%7D%20+%2010%20%5C,%20t" alt="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t" title="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t" data-latex="16 \, y^{3} {y'} + 2 \, t y {y'} - 8 \, t y - 5 \, t {y'} = 10 \, t y^{2} + 10 \, t">
</p>
<p style="text-align:center;">
<img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?16%20%5C,%20y%5E%7B3%7D%20%7By'%7D%20-%204%20%5C,%20t%5E%7B2%7D%20%7By'%7D%20-%2010%20%5C,%20t%20=%208%20%5C,%20t%20y" alt="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" title="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" data-latex="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t 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(%20-1%20)=%201" alt="y( -1 )= 1" title="y( -1 )= 1" data-latex="y( -1 )= 1">. </p>
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<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?16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" alt="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" title="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" data-latex="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t 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 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)" alt="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)" title="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)" data-latex="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)"/>
</p>
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<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?16%20%5C,%20y%5E%7B3%7D%20%7By'%7D%20-%204%20%5C,%20t%5E%7B2%7D%20%7By'%7D%20-%2010%20%5C,%20t%20=%208%20%5C,%20t%20y" alt="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" title="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t y" data-latex="16 \, y^{3} {y'} - 4 \, t^{2} {y'} - 10 \, t = 8 \, t 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,%20y%5E%7B4%7D%20-%204%20%5C,%20t%5E%7B2%7D%20y%20-%205%20%5C,%20t%5E%7B2%7D%20=%20%5Cleft(-5%5Cright)" alt="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)" title="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)" data-latex="4 \, y^{4} - 4 \, t^{2} y - 5 \, t^{2} = \left(-5\right)">
</p>
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