creates a cube with side length
    $2.3$ units instead of 2 units. Note that the volume of the
    cube is $V=s^3$. Use a first, second, and third order
    approximation to estimate the increase in volume caused by the
    .3 increase in side length. Then compute the actual increase in
    volume $V(2.3)-V(2)$.</p>
  </div>

  <div class="note">
    I would include this problem above in class as a demonstration.
    It allows them to see what differentials do. You can easily see
    how each new piece add