Question
The magnitude of projection of line joining (3,4, 5) and (4,6,3) on the line joining (-1,2,4) and (1,0,5) is
BITSAT
Mathematics
Three Dimensional Geometry
2024
BITSAT 2024 (Memory Based Paper 3)
BITSAT Mathematics Question (2024) — Solution
Options
- A. 4 3
- B. 2 3
- C. 8 3
- D. 1 3
Answer
A. 4 3
Step-by-step solution
We know that, projection of a on b is given by projection, | a | = ( a b ) | b | Let line joining points (3,4,5) and (4,6,3) is L_1 and line joining points (-1,2,4) and (1,0,5) is L_2 aligned & L_1= i +2 j -2 k \\ & L_2=2 i -2 j + k aligned Projection of L_1 and L_2= L_1 L_2 |L_2 | = 2-4-2 4+4+1 = -4 3 Magnitude = 4 3
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