The following code is okay in the HTML version, but there is an error in the LaTeX version.
<statement>
<p>Show that
<me>\frac{dI}{dS} = -1 + \frac{1}{R_0S}.</me>
Two features of this new equation are particularly worth noting.
<ul>
<li><p>The only parameter that appears is <m>R_0</m>, the reproduction number.</p></li>
<li><p>The equation is independent of time. That is, what we learn about the relationship between <m>S</m> and <m>I</m> must be true for the entire duration of the pandemic.</p></li>
</ul>
Compute <m>d^2I/dS^2</m>. Determine when the number of infected will begin to decrease. Compare this to your result from <xref ref="systems05-task-I-increasing" />.</p>
</statement>
<hint>
<p>Use the chain rule.</p>
</hint>
</task>
I’m not sure what’s going on.