Q.

Let O be the origin and the position vectors of A and B be 2i^+2j^+k^ and 2i^+4j^+4k^ respectively. If the internal bisector of AOB meets the line AB at C, then the length of OC is          [2024]

1 2331  
2 3234  
3 2334  
4 3231  

Ans.

(3)

|OA|=4+4+1=3

|OB|=4+16+16=6

OAOB=ACCB=36=12

C(4+23,4+43,2+43)

  C(2,83,2)

|OC|=4+649+4=1363=2343.