<item ident="S1-1892" title="S1 | Phase Planes | ver. 1892">
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<div class="exercise-statement">
<p>
<strong>S1.</strong>
</p>
<p> Draw a phase plane for the following system of ODEs. </p>
<p style="text-align:center;">
<img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'= x - y - 2" alt="x'= x - y - 2" title="x'= x - y - 2" data-latex="x'= x - y - 2"/>
</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'= -2 \, x - y + 7" alt="y'= -2 \, x - y + 7" title="y'= -2 \, x - y + 7" data-latex="y'= -2 \, x - y + 7"/>
</p>
<p>Be sure to include and label the following features in your sketch:</p>
<ul>
<li>The isoclines <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'=0" alt="x'=0" title="x'=0" data-latex="x'=0"/> and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y'=0" alt="y'=0" title="y'=0" data-latex="y'=0"/>.</li>
<li>Arrow systems describing trajectories of solutions.</li>
<li>The equillibrium of the system.</li>
</ul>
</div>
</mattextxml>
<mattext texttype="text/html"><div class="exercise-statement">
<p>
<strong>S1.</strong>
</p>
<p> Draw a phase plane for the following system of ODEs. </p>
<p style="text-align:center;">
<img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'=%20x%20-%20y%20-%202" alt="x'= x - y - 2" title="x'= x - y - 2" data-latex="x'= x - y - 2">
</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'=%20-2%20%5C,%20x%20-%20y%20+%207" alt="y'= -2 \, x - y + 7" title="y'= -2 \, x - y + 7" data-latex="y'= -2 \, x - y + 7">
</p>
<p>Be sure to include and label the following features in your sketch:</p>
<ul>
<li>The isoclines <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'=0" alt="x'=0" title="x'=0" data-latex="x'=0"> and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y'=0" alt="y'=0" title="y'=0" data-latex="y'=0">.</li>
<li>Arrow systems describing trajectories of solutions.</li>
<li>The equillibrium of the system.</li>
</ul>
</div>
</mattext>
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<response_str ident="response1" rcardinality="Single">
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<response_label ident="answer1" rshuffle="No"/>
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<div class="exercise-answer">
<h4>Partial Answer:</h4>
<p> The isoclines cross at the equillibrium <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\left(3, 1\right)" alt="\left(3, 1\right)" title="\left(3, 1\right)" data-latex="\left(3, 1\right)"/>, with <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'=0" alt="x'=0" title="x'=0" data-latex="x'=0"/> having a positive slope and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y'=0" alt="y'=0" title="y'=0" data-latex="y'=0"/> having a negative slope. </p>
<p> The right region has a southeast arrow system, the top region has a southwest arrow system, the left region has a northwest arrow system, and the bottom region has a northeast arrow system. </p>
</div>
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<mattext texttype="text/html"><div class="exercise-answer">
<h4>Partial Answer:</h4>
<p> The isoclines cross at the equillibrium <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cleft(3,%201%5Cright)" alt="\left(3, 1\right)" title="\left(3, 1\right)" data-latex="\left(3, 1\right)">, with <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?x'=0" alt="x'=0" title="x'=0" data-latex="x'=0"> having a positive slope and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y'=0" alt="y'=0" title="y'=0" data-latex="y'=0"> having a negative slope. </p>
<p> The right region has a southeast arrow system, the top region has a southwest arrow system, the left region has a northwest arrow system, and the bottom region has a northeast arrow system. </p>
</div>
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