Let O be the origin and the position vector 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
(A)3231
(B)3234✓ Correct
(C)4334
(D)2331
Answer: (B)
Solution
O = origin, A=(2,2,1), B=(2,4,4). ∣OA∣=4+4+1=3, ∣OB∣=4+16+16=6.
The internal bisector of ∠AOB meets AB at C, dividing it in the ratio AC:CB=OA:OB=3:6=1:2: