 find a
      formula for $dV$ in terms of $dr$ when $h$ is constant.</li>

      <li>If the radius remains constant, but the height changes,
      what is $dV/dt$ in terms of $dh/dt$? What is $dV$ when $r$ is
      constant?</li>

      <li>If both the radius and height change, what is $dV/dt$ in
      terms of $dh/dt$ and $dr/dt$? Solve for $dV$.</li>

      <li>       <div class="marginpar">
          Make sure you ask me in class to show you physically
          exactly how you can see these differentia