Q. A straight line $L$ on the $xy$-plane bisects the angle between $OX$ and $OY$. What are the direction cosines of $L$?
A) $< (1/\sqrt{2}),(1/\sqrt{2}),0 >$
B) $< (1/2),\ (\sqrt{3}/2),0 >$
C) $< 0,\ 0,1 >$
D) $< (2/3),\ (2/3),\ (1/3) >$
Explanation
(a)
The given line makes angles of $\pi/4,\ \pi/4,\ \$and$\ \pi/2$ with the $x$-$,\ y$- and $z$-axes, respectively,
$\Rightarrow$ Direction cosines of the given line are
$\cos{(\pi/4)},\cos{(\pi/4)}$ and $\cos{(\pi/2)}$, or $(1/\sqrt{2}),(1/\sqrt{2})$ and 0
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.