9709 P33 - Nov 2014 - Q7
2155
The equations of two straight lines are
\(\mathbf{r} = \mathbf{i} + 4\mathbf{j} - 2\mathbf{k} + \lambda(\mathbf{i} + 3\mathbf{k})\) and \(\mathbf{r} = a\mathbf{i} + 2\mathbf{j} - 2\mathbf{k} + \mu(\mathbf{i} + 2\mathbf{j} + 3a\mathbf{k})\),
where \(a\) is a constant.
- Show that the lines intersect for all values of \(a\).
- Given that the point of intersection is at a distance of 9 units from the origin, find the possible values of \(a\).
