<exercise>
<statement>
<p>Let <m>A</m> be a <m>4 \times 4</m> matrix.</p>
<ol>
<li>Give a <m>4 \times 4</m> matrix <m><xsl:value-of select="name1"/></m> that may be used to perform the row operation <m><xsl:value-of select="row_op1"/></m>.</li>
<li>Give a <m>4 \times 4</m> matrix <m><xsl:value-of select="name2"/></m> that may be used to perform the row operation <m><xsl:value-of select="row_op2"/></m>.</li>
<li>Use matrix multiplication to describe the matrix obtained by applying
<xsl:choose>
<xsl:when test="swapped"><m><xsl:value-of select="row_op2"/></m> and then <m><xsl:value-of select="row_op1"/></m></xsl:when>
<xsl:otherwise><m><xsl:value-of select="row_op1"/></m> and then <m><xsl:value-of select="row_op2"/></m></xsl:otherwise>
</xsl:choose>
to <m>A</m> (note the order).
</li>
</ol>
</statement>
<answer>
<ol>
<li><m><xsl:value-of select="name1"/>=<xsl:value-of select="mat1"/></m></li>
<li><m><xsl:value-of select="name2"/>=<xsl:value-of select="mat2"/></m></li>
<li>
<xsl:choose>
<xsl:when test="swapped"><m><xsl:value-of select="name1"/><xsl:value-of select="name2"/>A</m></xsl:when>
<xsl:otherwise><m><xsl:value-of select="name2"/><xsl:value-of select="name1"/>A</m></xsl:otherwise>
</xsl:choose>
</li>
</ol>
</answer>
</exercise>