The line \(l_1\) passes through the points \(A\) and \(B\) with position vectors \((\mathbf{3i} + \mathbf{6j} - \mathbf{8k})\) and \((\mathbf{8j} - \mathbf{6k})\) respectively, relative to a fixed origin.
- Find a vector equation for \(l_1\). [2]
The line \(l_2\) has vector equation
$$\mathbf{r} = (-\mathbf{2i} + \mathbf{10j} + \mathbf{6k}) + \mu(\mathbf{7i} - \mathbf{4j} + \mathbf{6k}),$$
where \(\mu\) is a scalar parameter.
- Show that lines \(l_1\) and \(l_2\) intersect. [4]
- Find the coordinates of the point where \(l_1\) and \(l_2\) intersect. [2]
The point \(C\) lies on \(l_2\) and is such that \(AC\) is perpendicular to \(AB\).
- Find the position vector of \(C\). [6]