782cd189-a37c-464a-8169-69bb63689cef.html

<p>In this lesson, students used exponential functions to answer questions about different situations. In a previous lesson, they saw that a function \(f\) defined by \(f(t)=240(\frac13)^t\) represents the area of algae in square yards after \(t\)<em>&nbsp;</em>weeks of treatment. Discuss how the equation could be used to:</p>
<ul>
  <li>produce a graph.</li>
  <li>find the area of the algae 6 weeks after treatment.</li>
  <li>find out when the area of the algae would drop below 10 square yards.</li>
</ul>
<p>Ask students what \(f(1)=80\) and \(f(2)=\frac{80}{3}\) mean in this context. To reiterate the importance of choosing an appropriate graphing window, ask students to give examples of a graphing window that would be appropriate (or inappropriate) for this function. Time permitting, demonstrate the outcomes of their suggestions using graphing technology.</p>