Three Dimensional Geometry Question 129
Question: If O is the origin and $ OP=3 $ with direction ratios $ -1,,2,-2 $ , then co-ordinates of P are
[RPET 2000; DCE 2005]
Options:
A) (1, 2, 2)
B) $ (-1,,2,,-2) $
C) (?3, 6, ?9)
D) $ (-1/3,,,2/3,,-2/3) $
Show Answer
Answer:
Correct Answer: B
Solution:
Co-ordinates of P are $ (lr,,mr,,nr) $ Here $ l=\frac{-1}{\sqrt{1^{2}+2^{2}+2^{2}}}=\frac{-1}{3},,m=\frac{2}{3},,n=\frac{-2}{3} $ and $ r=3, $ , (given) \ Co-ordinates of P are (?1, 2, ?2).
BETA
