an><span class="fl">1</span> <span class="op">+</span> <span class="fu"><a href="https://rdrr.io/r/base/Log.html" class="external-link">exp</a></span><span class="op">(</span><span class="va">b1</span><span class="op">*</span><span class="op">(</span><span class="va">x</span><span class="op">-</span><span class="va">x0</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span>  <span class="va">S</span> <span class="op">&lt;-</span> <span class=