nerJZr5twv-rDoXdqbpPzRth1aNTU3N3sszNFD5mWFJ42rANZVesT-jNgN3HoyGzT9WBDrDI_KvfXDD46EMa_kouixmtwt6diKe_OvC8aA">
      Sage</a>.
    </div>

    <div class="marginpar">
      <span class="bmw">See 16.5: 27-30 for more
      practice.</span><span class="larsonfive">See Larson
      15.5:35&ndash;38 for more practice.</span>
    </div> Consider the cone parametrized by $\vec r(u,v)=(u\cos
    v, u\sin v,u)$.

    <ol>
      <li>Give vector equations of two tangent lines to the surface
      at $\vec r(2,\pi/2)$ (