Question

find the direction cosines of a line segment joining the points: P(2,-1,3) and Q(3,1,1)

Answer 1

Ř = ă + t( b - a)
So (B - A) = Č = (3-2 , 1 +1, 1-3) = (1,2,-2)
Direction cosines = Č/|C|
|C| = (1² + 2² + 2²)^½ = 3
Thus it would be,
1/3, 2/3, - 2/3 ans.
Hope I helped you.

Answer 2

yes the same answer. holpe