Matrix input - mkraska/meclib GitHub Wiki
M: matrix( [a, b], [c, d] );
The size of the model answer sets the size of the input.
A matrix input is a block of its own, so label, input, unit and validation go into one table row:
<table border="0">
<tbody>
<tr>
<td>\( \left[ \begin{array}{cc} a & b \\ c & d \end{array} \right] = \) </td>
<td>[[input:S_M]]</td>
<td>\(\, optional unit\)</td>
<td>[[validation:S_M]]</td>
</tr>
</tbody>
</table>
<p>[[feedback:M]]</p>
Feedback: fb_unit_matrix() for numbers, fb_vars_matrix() for expressions, see also Matrix Feedback.