Question: The lines $ 2x=3y=-z $ and $ 6x=-y=-4z $
Options:
A) Are perpendicular
B) Are parallel
C) $ intersectatanangle45{}^\circ $
D) $ intersectatanangle60{}^\circ $
Show Answer
Answer:
Correct Answer: A
Solution:
- [a] $ 2x=3y=-z $ or $ \frac{x}{3}=\frac{y}{2}=\frac{z}{-6} $ $ 6x=-y=-4z $ or $ \frac{x}{2}=\frac{y}{-12}=\frac{z}{-3} $ $ \cos \theta =\frac{x_1x_2+y_1y_2+z_1z_2}{\sqrt{x^2_1+x^2_2+x^2_3}.\sqrt{y^2_1+y^2_2+y^2_3}} $ $ =\frac{(6-24+18)}{\sqrt{{{(3)}^{2}}-{{(2)}^{2}}+{{(-6)}^{2}}}.\sqrt{2{{{{(}^{2}}+-12)}^{2}}+{{(-3)}^{2}}}} $ $ \cos \theta =0 $ $ \theta =90{}^\circ $ So lines are perpendicular