Question

If the line $\overrightarrow{OR}$ makes angles ${\theta }_1,{\theta }_2,{\theta }_3$ with the planes $XOY,YOZ,ZOX$ respectively, then ${\cos }^2{\theta }_1+{\cos }^2{\theta }_2+{\cos }^2{\theta }_3$ is equal to

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

The correct option is A $1$

If the line $\overrightarrow{OR}$ makes angles ${\theta }_1,{\theta }_2,{\theta }_3$ with the planes $XOY,YOZ,ZOX$ respectively, then ${\cos }^2{\theta }_1+{\cos }^2{\theta }_2+{\cos }^2{\theta }_3$ $=1$