Three Dimensional Geometry Question 182
If the direction ratios of two lines are given by $ 3l^2m-4l^2n+mn=0 $ and $ l+2m+3n=0 $ , then the angle between the lines is
[EAMCET 2003]
Options:
A) $ \pi /2 $
B) $ \pi /3 $
C) $ \pi /4 $
D) $ \pi /6 $
Show Answer
Answer:
Correct Answer: A
Solution:
By solving two equations, $ (l_1,,m_1,,n_1)=(2\sqrt{2}-3,,-\sqrt{2},,1) $ $ (l_2,,m_2,,n_2)=(-2\sqrt{2}-3,,\sqrt{2},,1) $ $ l_1l_2+m_1m_2+n_1n_2=0 $ \ The angle between them is $ \pi /2 $ .
BETA
