(X_{0:5} = (X_0, X_1, X_2, X_3, X_4)\)</span>.
Here is another:</p>
<div class="math notranslate nohighlight" id="equation-this-is-a-label">
<span class="eqno">(1)<a class="headerlink" href="#equation-this-is-a-label" title="Permalink to this equation">¶</a></span>\[\nabla^2 f =
\frac{1}{r^2} \frac{\partial}{\partial r}
\left( r^2 \frac{\partial f}{\partial r} \right) +
\frac{1}{r^2 \sin \theta} \frac{\partial f}{\partial \theta}
\left( \sin \theta \, \frac{\partial f}{\partial \theta} \right) +
\frac{1}{r