m-1">this part</a>, and write the temperature
        on each level curve you draw.
      </li>

      <li>
        <div class="marginpar">
          This idea leads to an optimization technique, Lagrange
          multipliers, later in the semester.
        </div>
          As the horse runs around, the temperature of the
        air around the horse is constantly changing. At which $t$
        does the temperature around the horse reach a maximum? A
        minimum? Explain, using your graph.
      </li>
