Home › JEE Advanced › Mathematics › Surface Areas and Volumes › The direction cosines of a line whose direction …
The direction cosines of a line whose direction ratios are $2,-1,2$ are:
A$2, -1, 2$
B$\tfrac12, -\tfrac11, \tfrac12$
C$\tfrac29, -\tfrac19, \tfrac29$
D$\tfrac23, -\tfrac13, \tfrac23$
Answer & Solution
Correct answer: D. $\tfrac23, -\tfrac13, \tfrac23$
Divide by √(2²+1²+2²)=3: direction cosines are (2/3, −1/3, 2/3).
Related questions
Painting the outside of a toy needs to be worked out from its:Breaking a hard problem into solved smaller ones is the method:A cylindrical tube with a rounded end is a cylinder with a:Pouring a liquid into a container of another shape keeps its:Joining two solids at their flat faces hides those faces:Which solid is not among the basic ones met earlier?The word frustum comes from Latin, meaning a piece:The two circular ends of a frustum have radii that are: