 infinity, <code>xc</code> will be NaN.</p>
<p>For zero-crossing definite integrals (see section <a href="#zero-crossing">Zero Crossing</a>) the integrals are broken into two pieces (<span class="math inline">\((a, 0)\)</span> and <span class="math inline">\((0, b)\)</span> for endpoints <span class="math inline">\(a &lt; 0\)</span> and <span class="math inline">\(b &gt; 0\)</span>) and <code>xc</code> is a high precision version of the distance to the limits of each of the two integrals separately. This me