Question

For the lines \[\vec r=\vec a_1+\lambda\vec b_1\] and \[\vec r=\vec a_2+\mu\vec b_2\], the angle between the lines is the angle between:

Options

• \[\vec b_1\] and \[\vec b_2\]

• \[\vec a_1\] and \[\vec a_2\]

• \[\lambda\] and \[\mu\]

• \[\vec a_1+\vec a_2\] and \[\vec b_1+\vec b_2\]

Answer 1

In vector form, \[\vec b_1\] and \[\vec b_2\] are the direction vectors. Hence, the angle between the lines is obtained from the angle between these vectors.