JEE Main202429 Jan 2024Morning ShiftMathematicsThree Dimensional GeometryActual
Let O be the origin and the position vector of A and B be 2 i ^ + 2 j ^ + k ^ and 2 i ^ + 4 j ^ + 4 k ^ respectively. If the internal bisector of ∠ A O B meets the line A B at C , then the length of O C is
Options
- A2 3 31
- B2 3 34
- C3 4 34
- D3 2 31
Correct answer
B. 2 3 34
Step-by-step solution
We know that, the internal bisector divides base in the same ratio as the two remaining sides. ⇒ O A O B = A C B C ⇒ 2 2 + 2 2 + 1 2 2 2 + 4 2 + 4 2 = A C B C ⇒ 3 6 = A C B C ⇒ A C : B C = 1 : 2 ⇒ C ≡ 1 × 2 + 2 × 2 3 , 1 × 4 + 2 × 2 3 , 1 × 4 + 2 × 1 3 ⇒ C ≡ 2 , 8 3 , 2 ⇒ O C = 2 2 + 8 3 2 + 2 2 ⇒ O C = 8 + 64 9 = 136 3 ⇒ O C = 2 34 3