<item ident="F5-7332" title="F5 | Substitution strategies | ver. 7332"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>F5.</strong> </p> <p> Apply each of the substitutions <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?u=\frac{y}{t}" alt="u=\frac{y}{t}" title="u=\frac{y}{t}" data-latex="u=\frac{y}{t}"/> and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?u=at+by+c" alt="u=at+by+c" title="u=at+by+c" data-latex="u=at+by+c"/> to one of the following ODEs, and show that each result is separable. (Do not fully solve either ODE.) </p> <ol type="a"> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?0 = -t y {y'} - 3 \, t^{2} - y^{2}" alt="0 = -t y {y'} - 3 \, t^{2} - y^{2}" title="0 = -t y {y'} - 3 \, t^{2} - y^{2}" data-latex="0 = -t y {y'} - 3 \, t^{2} - y^{2}"/> </li> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4" alt="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4" title="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4" data-latex="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4"/> </li> </ol> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>F5.</strong> </p> <p> Apply each of the substitutions <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?u=%5Cfrac%7By%7D%7Bt%7D" alt="u=\frac{y}{t}" title="u=\frac{y}{t}" data-latex="u=\frac{y}{t}"> and <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?u=at+by+c" alt="u=at+by+c" title="u=at+by+c" data-latex="u=at+by+c"> to one of the following ODEs, and show that each result is separable. (Do not fully solve either ODE.) </p> <ol type="a"> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?0%20=%20-t%20y%20%7By'%7D%20-%203%20%5C,%20t%5E%7B2%7D%20-%20y%5E%7B2%7D" alt="0 = -t y {y'} - 3 \, t^{2} - y^{2}" title="0 = -t y {y'} - 3 \, t^{2} - y^{2}" data-latex="0 = -t y {y'} - 3 \, t^{2} - y^{2}"> </li> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%7By'%7D%20+%20%5Cfrac%7B2%7D%7B2%20%5C,%20t%20+%20y%20+%202%7D%20=%202%20%5C,%20t%20+%20y%20+%204" alt="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4" title="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4" data-latex="{y'} + \frac{2}{2 \, t + y + 2} = 2 \, t + y + 4"> </li> </ol> </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> <ol type="a"> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}" alt="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}" title="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}" data-latex="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}"/> </li> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\frac{u {u'}}{u^{2} - 2} = 1" alt="\frac{u {u'}}{u^{2} - 2} = 1" title="\frac{u {u'}}{u^{2} - 2} = 1" data-latex="\frac{u {u'}}{u^{2} - 2} = 1"/> </li> </ol> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <ol type="a"> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cfrac%7Bu%20%7Bu'%7D%7D%7Bu%5E%7B2%7D%20+%203%7D%20=%20%5Cfrac%7B1%7D%7Bt%7D" alt="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}" title="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}" data-latex="\frac{u {u'}}{u^{2} + 3} = \frac{1}{t}"> </li> <li> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Cfrac%7Bu%20%7Bu'%7D%7D%7Bu%5E%7B2%7D%20-%202%7D%20=%201" alt="\frac{u {u'}}{u^{2} - 2} = 1" title="\frac{u {u'}}{u^{2} - 2} = 1" data-latex="\frac{u {u'}}{u^{2} - 2} = 1"> </li> </ol> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>