4 The lines \(l _ { 1 }\) and \(l _ { 2 }\) have equations
$$\mathbf { r } = \left( \begin{array} { l }
1
2
1
\end{array} \right) + \lambda \left( \begin{array} { r }
2
3
- 1
\end{array} \right) \text { and } \mathbf { r } = \left( \begin{array} { l }
3
0
1
\end{array} \right) + \mu \left( \begin{array} { r }
4
- 1
- 1
\end{array} \right)$$
respectively.
- Find the shortest distance between the lines.
- Find a cartesian equation of the plane which contains \(l _ { 1 }\) and which is parallel to \(l _ { 2 }\).