in{equation}
f(t; t_1, t_2, t_3, k, \beta) =
\begin{cases}
0 &amp; \text{if } t &lt; t_1 \\
\dfrac{k}{t_2 - t_1} \cdot (t - t_1) &amp; \text{if } t_1 \leq t \leq
t_2 \\
k &amp; \text{if } t_2 \leq t \leq t_3 \\
k + \beta \cdot (t - t_3) &amp; \text{if } t &gt; t_3
\end{cases}
\end{equation}\]</span></p>
<div class="sourceCode" id="cb5"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span class="fu"><a href="../reference/plot_fn.html">plot_fn</a></span><span class="op">(</span></span>
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