<item ident="M3-0010" title="M3 | Invertible matrices | ver. 0010"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>M3.</strong> </p> <p>Explain why the matrix <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?Q= \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right]" alt="Q= \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right]" title="Q= \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right]" data-latex="Q= \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right]"/> is or is not invertible.</p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>M3.</strong> </p> <p>Explain why the matrix <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?Q=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D%20-3%20&amp;%20-3%20&amp;%201%20&amp;%201%20%5C%5C%204%20&amp;%205%20&amp;%20-2%20&amp;%20-2%20%5C%5C%20-4%20&amp;%20-4%20&amp;%201%20&amp;%203%20%5C%5C%20-3%20&amp;%20-3%20&amp;%200%20&amp;%207%20%5Cend%7Barray%7D%5Cright%5D" alt="Q= \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right]" title="Q= \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right]" data-latex="Q= \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right]"> is or is not invertible.</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><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}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right] = \left[\begin{array}{cccc} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}\right]" alt="\operatorname{RREF} \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right] = \left[\begin{array}{cccc} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}\right]" title="\operatorname{RREF} \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right] = \left[\begin{array}{cccc} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}\right]" data-latex="\operatorname{RREF} \left[\begin{array}{cccc} -3 & -3 & 1 & 1 \\ 4 & 5 & -2 & -2 \\ -4 & -4 & 1 & 3 \\ -3 & -3 & 0 & 7 \end{array}\right] = \left[\begin{array}{cccc} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}\right]"/></p></p><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?Q" alt="Q" title="Q" data-latex="Q"/> is invertible.</div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <p></p> <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%7Bcccc%7D%20-3%20&amp;%20-3%20&amp;%201%20&amp;%201%20%5C%5C%204%20&amp;%205%20&amp;%20-2%20&amp;%20-2%20%5C%5C%20-4%20&amp;%20-4%20&amp;%201%20&amp;%203%20%5C%5C%20-3%20&amp;%20-3%20&amp;%200%20&amp;%207%20%5Cend%7Barray%7D%5Cright%5D%20=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D%201%20&amp;%200%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%201%20&amp;%200%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%201%20&amp;%200%20%5C%5C%200%20&amp;%200%20&amp;%200%20&amp;%201%20%5Cend%7Barray%7D%5Cright%5D" alt="\operatorname{RREF} \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right] = \left[\begin{array}{cccc} 1 &amp; 0 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 1 &amp; 0 \\ 0 &amp; 0 &amp; 0 &amp; 1 \end{array}\right]" title="\operatorname{RREF} \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right] = \left[\begin{array}{cccc} 1 &amp; 0 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 1 &amp; 0 \\ 0 &amp; 0 &amp; 0 &amp; 1 \end{array}\right]" data-latex="\operatorname{RREF} \left[\begin{array}{cccc} -3 &amp; -3 &amp; 1 &amp; 1 \\ 4 &amp; 5 &amp; -2 &amp; -2 \\ -4 &amp; -4 &amp; 1 &amp; 3 \\ -3 &amp; -3 &amp; 0 &amp; 7 \end{array}\right] = \left[\begin{array}{cccc} 1 &amp; 0 &amp; 0 &amp; 0 \\ 0 &amp; 1 &amp; 0 &amp; 0 \\ 0 &amp; 0 &amp; 1 &amp; 0 \\ 0 &amp; 0 &amp; 0 &amp; 1 \end{array}\right]"></p> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?Q" alt="Q" title="Q" data-latex="Q"> is invertible.</div> </mattext> </material> </flow_mat> </itemfeedback> </item>