<item ident="M1-0004" title="M1 | Multiplying matrices | ver. 0004"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>M1.</strong> </p> <p>Of the following three matrices, only two may be multiplied. <p style="text-align:center;"><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?A= \left[\begin{array}{ccc} 2 & -1 & -1 \\ 1 & 0 & -2 \\ 3 & -1 & -2 \\ 2 & -1 & -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 & 3 \\ 0 & 1 \\ -2 & -2 \\ 1 & 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 & 5 & -3 \\ 1 & 2 & -1 \end{array}\right]" alt="A= \left[\begin{array}{ccc} 2 & -1 & -1 \\ 1 & 0 & -2 \\ 3 & -1 & -2 \\ 2 & -1 & -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 & 3 \\ 0 & 1 \\ -2 & -2 \\ 1 & 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 & 5 & -3 \\ 1 & 2 & -1 \end{array}\right]" title="A= \left[\begin{array}{ccc} 2 & -1 & -1 \\ 1 & 0 & -2 \\ 3 & -1 & -2 \\ 2 & -1 & -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 & 3 \\ 0 & 1 \\ -2 & -2 \\ 1 & 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 & 5 & -3 \\ 1 & 2 & -1 \end{array}\right]" data-latex="A= \left[\begin{array}{ccc} 2 & -1 & -1 \\ 1 & 0 & -2 \\ 3 & -1 & -2 \\ 2 & -1 & -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 & 3 \\ 0 & 1 \\ -2 & -2 \\ 1 & 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 & 5 & -3 \\ 1 & 2 & -1 \end{array}\right]"/></p> Explain which two can be multiplied and why. Then show how to find their product.</p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>M1.</strong> </p> <p>Of the following three matrices, only two may be multiplied. </p> <p style="text-align:center;"><img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?A=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%202%20&amp;%20-1%20&amp;%20-1%20%5C%5C%201%20&amp;%200%20&amp;%20-2%20%5C%5C%203%20&amp;%20-1%20&amp;%20-2%20%5C%5C%202%20&amp;%20-1%20&amp;%20-1%20%5Cend%7Barray%7D%5Cright%5D%20%5Chspace%7B1em%7D%20B=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D%203%20&amp;%203%20%5C%5C%200%20&amp;%201%20%5C%5C%20-2%20&amp;%20-2%20%5C%5C%201%20&amp;%200%20%5Cend%7Barray%7D%5Cright%5D%20%5Chspace%7B1em%7D%20C=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%203%20&amp;%205%20&amp;%20-3%20%5C%5C%201%20&amp;%202%20&amp;%20-1%20%5Cend%7Barray%7D%5Cright%5D" alt="A= \left[\begin{array}{ccc} 2 &amp; -1 &amp; -1 \\ 1 &amp; 0 &amp; -2 \\ 3 &amp; -1 &amp; -2 \\ 2 &amp; -1 &amp; -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 &amp; 3 \\ 0 &amp; 1 \\ -2 &amp; -2 \\ 1 &amp; 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 &amp; 5 &amp; -3 \\ 1 &amp; 2 &amp; -1 \end{array}\right]" title="A= \left[\begin{array}{ccc} 2 &amp; -1 &amp; -1 \\ 1 &amp; 0 &amp; -2 \\ 3 &amp; -1 &amp; -2 \\ 2 &amp; -1 &amp; -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 &amp; 3 \\ 0 &amp; 1 \\ -2 &amp; -2 \\ 1 &amp; 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 &amp; 5 &amp; -3 \\ 1 &amp; 2 &amp; -1 \end{array}\right]" data-latex="A= \left[\begin{array}{ccc} 2 &amp; -1 &amp; -1 \\ 1 &amp; 0 &amp; -2 \\ 3 &amp; -1 &amp; -2 \\ 2 &amp; -1 &amp; -1 \end{array}\right] \hspace{1em} B= \left[\begin{array}{cc} 3 &amp; 3 \\ 0 &amp; 1 \\ -2 &amp; -2 \\ 1 &amp; 0 \end{array}\right] \hspace{1em} C= \left[\begin{array}{ccc} 3 &amp; 5 &amp; -3 \\ 1 &amp; 2 &amp; -1 \end{array}\right]"></p> Explain which two can be multiplied and why. Then show how to find their product. </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 style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?BC= \left[\begin{array}{ccc} 12 & 21 & -12 \\ 1 & 2 & -1 \\ -8 & -14 & 8 \\ 3 & 5 & -3 \end{array}\right]" alt="BC= \left[\begin{array}{ccc} 12 & 21 & -12 \\ 1 & 2 & -1 \\ -8 & -14 & 8 \\ 3 & 5 & -3 \end{array}\right]" title="BC= \left[\begin{array}{ccc} 12 & 21 & -12 \\ 1 & 2 & -1 \\ -8 & -14 & 8 \\ 3 & 5 & -3 \end{array}\right]" data-latex="BC= \left[\begin{array}{ccc} 12 & 21 & -12 \\ 1 & 2 & -1 \\ -8 & -14 & 8 \\ 3 & 5 & -3 \end{array}\right]"/> </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?BC=%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%2012%20&amp;%2021%20&amp;%20-12%20%5C%5C%201%20&amp;%202%20&amp;%20-1%20%5C%5C%20-8%20&amp;%20-14%20&amp;%208%20%5C%5C%203%20&amp;%205%20&amp;%20-3%20%5Cend%7Barray%7D%5Cright%5D" alt="BC= \left[\begin{array}{ccc} 12 &amp; 21 &amp; -12 \\ 1 &amp; 2 &amp; -1 \\ -8 &amp; -14 &amp; 8 \\ 3 &amp; 5 &amp; -3 \end{array}\right]" title="BC= \left[\begin{array}{ccc} 12 &amp; 21 &amp; -12 \\ 1 &amp; 2 &amp; -1 \\ -8 &amp; -14 &amp; 8 \\ 3 &amp; 5 &amp; -3 \end{array}\right]" data-latex="BC= \left[\begin{array}{ccc} 12 &amp; 21 &amp; -12 \\ 1 &amp; 2 &amp; -1 \\ -8 &amp; -14 &amp; 8 \\ 3 &amp; 5 &amp; -3 \end{array}\right]"> </p> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>