 the steps below, but instead try to follow
    the patterns in the previous problem on your own.

    <ol>
      <li>Rewrite the equations for $x$, $y$, and $z$ in vector form
      $\vec r(u,v)=(x,y,z)$. If you were to graph $\vec r$, what
      kind of graph would you make?</li>

      <li>Compute the derivatives $Df(x,y,z)$ and $D\vec r(u,v)$,
      and then multiply them together. Notice that since this
      composite function has 2 inputs, namely $u$ and $v$, we
      should expect to get two columns