Manipal MET2019MathematicsThree Dimensional Geometry
If (3,4,5), Q(4,6,3), R(-1,2,4), S(1,0,5) , then the projection of R S on P Q is
Options
- A- 2 3
- B- 4 3
- C1 2
- D2
Correct answer
B. - 4 3
Step-by-step solution
We have, P(3,4,5), Q(4,6,3), R(-1,2,4) and S(1,0,5) . Direction ratios of P Q are (1,2,-2) and direction cosines of P Q are 1 1^2+2^2+(-2)^2 , 2 1^2+2^2+(-2)^2 -2 1^2+2^2+(-2)^2 = 1 9 , 2 9 ,- 2 9 = 1 3 , 2 3 ,- 2 3 Required projection of R S on P Q is l (x₂-x₁ )+m (y₂-y₁ )+n (z₂-z₁ )