p; 0\\0 &amp; 0 &amp; - a &amp; 1\end{matrix}\right] \left[\begin{matrix}x_{0}\\x_{1}\\x_{2}\\x_{3}\end{matrix}\right] = L_1 x
\]</span></p>
<div class="sourceCode" id="cb2"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span class="va">N</span> <span class="op">&lt;-</span> <span class="fl">3</span>
<span class="va">L1</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/diag.html">diag</a></span><span class="op">(</span><span class="fl">4</span><span class="op">)</sp