A power cable is to be fitted under a road and can be represented on 3D Cartesian axes as below, with the x-axis pointing East, the y-axis North, and the z-axis vertical. The pipeline is to consist of a straight section AB directly under the road, and another straight section BC connected to the first. All lengths are in metres.
a. Evaluate the distance AB.
The section BC is to be drilled in the direction of the vector 3i + 4j + k.
b. Find the angle between the sections AB and BC.
The section of pipe reaches ground level at the point C(a, b, 0).
c. Write down a vector equation of the line BC. Hence find a and b.