If and are unit vectors such that is a unit vector, what is the angle between and ?

If P(1, 5, 4) and Q(4, 1, - 2) be the position vectors of two points P and Q, find the direction ratios of

Find the direction cosines of the vector .

Mark (√) against the correct answer in each of the following:

A unit vector in the direction of the vector is

Mark (√) against the correct answer in each of the following:

A unit vector in the direction of the vector is