<item ident="E2-0010" title="E2 | Reduced row echelon form | ver. 0010">
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<fieldentry>essay_question</fieldentry>
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<presentation>
<material>
<mattextxml>
<div class="exercise-statement">
<p>
<strong>E2.</strong>
</p>
<ol type="a">
<li>Show that <p style="text-align:center;"><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." alt="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." title="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." data-latex="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ."/></p></li>
<li>Explain why the matrix <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?B= \left[\begin{array}{ccc} 1 & -2 & 2 \\ 0 & 1 & -1 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right]" alt="B= \left[\begin{array}{ccc} 1 & -2 & 2 \\ 0 & 1 & -1 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right]" title="B= \left[\begin{array}{ccc} 1 & -2 & 2 \\ 0 & 1 & -1 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right]" data-latex="B= \left[\begin{array}{ccc} 1 & -2 & 2 \\ 0 & 1 & -1 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right]"/> is or is not in reduced row echelon form.</li>
</ol>
</div>
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<mattext texttype="text/html"><div class="exercise-statement">
<p>
<strong>E2.</strong>
</p>
<ol type="a">
<li>Show that <p style="text-align:center;"><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?%5Coperatorname%7BRREF%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%201%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%201%20&amp;%20-2%20%5C%5C%201%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%202%20&amp;%20-4%20%5Cend%7Barray%7D%5Cright%5D%20=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%201%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%201%20&amp;%20-2%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5Cend%7Barray%7D%5Cright%5D%20." alt="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] ." title="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] ." data-latex="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] ."></p>
</li>
<li>Explain why the matrix <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?B=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%201%20&amp;%20-2%20&amp;%202%20%5C%5C%200%20&amp;%201%20&amp;%20-1%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5Cend%7Barray%7D%5Cright%5D" alt="B= \left[\begin{array}{ccc} 1 &amp; -2 &amp; 2 \\ 0 &amp; 1 &amp; -1 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right]" title="B= \left[\begin{array}{ccc} 1 &amp; -2 &amp; 2 \\ 0 &amp; 1 &amp; -1 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right]" data-latex="B= \left[\begin{array}{ccc} 1 &amp; -2 &amp; 2 \\ 0 &amp; 1 &amp; -1 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right]"> is or is not in reduced row echelon form.</li>
</ol>
</div>
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<response_str ident="response1" rcardinality="Single">
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<response_label ident="answer1" rshuffle="No"/>
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<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?\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." alt="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." title="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ." data-latex="\operatorname{RREF} \left[\begin{array}{ccc} 1 & -3 & 6 \\ 0 & 1 & -2 \\ 1 & -3 & 6 \\ 0 & -3 & 6 \\ 0 & 2 & -4 \end{array}\right] = \left[\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -2 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end{array}\right] ."/>
</li>
<li><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?B" alt="B" title="B" data-latex="B"/> is not in reduced row echelon form because not every entry above and below each pivot is zero. </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?%5Coperatorname%7BRREF%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%201%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%201%20&amp;%20-2%20%5C%5C%201%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%20-3%20&amp;%206%20%5C%5C%200%20&amp;%202%20&amp;%20-4%20%5Cend%7Barray%7D%5Cright%5D%20=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%201%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%201%20&amp;%20-2%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20%5Cend%7Barray%7D%5Cright%5D%20." alt="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] ." title="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] ." data-latex="\operatorname{RREF} \left[\begin{array}{ccc} 1 &amp; -3 &amp; 6 \\ 0 &amp; 1 &amp; -2 \\ 1 &amp; -3 &amp; 6 \\ 0 &amp; -3 &amp; 6 \\ 0 &amp; 2 &amp; -4 \end{array}\right] = \left[\begin{array}{ccc} 1 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; -2 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 0 \end{array}\right] .">
</li>
<li>
<img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?B" alt="B" title="B" data-latex="B"> is not in reduced row echelon form because not every entry above and below each pivot is zero. </li>
</ol>
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