Q. 24.3( 9 Votes )

If a line has direction ratios 2, –1, –2, determine its cosines.

Answer :

Let us assume the direction ratios of the line be r1, r2, r3.


Then:


r1 = 2


r2 = –1


r3 = –2


Let us assume the direction cosines for the line be l, m, n


We know that for a line of direction ratios r1, r2, r3 and having direction cosines l, m, n has the following property.





Let us substitute the values of r1, r2, r3 to find the values of .














The direction cosines for the given line is .

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Questions Based on 3D GeometryQuestions Based on 3D GeometryQuestions Based on 3D Geometry26 mins
Revision of straight lines important formulas in one shotRevision of straight lines important formulas in one shotRevision of straight lines important formulas in one shot59 mins
Concept Builder Questions of straight Lines (Quiz Session)Concept Builder Questions of straight Lines (Quiz Session)Concept Builder Questions of straight Lines (Quiz Session)55 mins
Reminding 11th - Revision of Circles important formulas in 50 MinutesReminding 11th - Revision of Circles important formulas in 50 MinutesReminding 11th - Revision of Circles important formulas in 50 Minutes56 mins
Conic Section Part 1Conic Section Part 1Conic Section Part 164 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses