/code></pre>

<pre><code>## (b1*x1/(b2 + x1), b1*x2/(b2 + x2), b1*x3/(b2 + x3))
</code></pre>

<h3>gradients</h3>

<pre><code class="r">g1 &lt;- der(mu1, b)
g2 &lt;- der(mu2, b)
g3 &lt;- der(mu3, b)
g1
</code></pre>

<pre><code>## [caracas]: ⎡           ⎡ -b₁⋅x₁   ⎤⎤
##            ⎢           ⎢──────────⎥⎥
##            ⎢⎡   x₁  ⎤  ⎢         2⎥⎥
##            ⎢⎢───────⎥  ⎢(b₂ + x₁) ⎥⎥
##            ⎢⎢b₂ + x₁⎥  �