CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The angle between the straight lines, whose direction cosines are given by the equations 2l+2mn=0 and mn+nl+lm=0, is

A
π3
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
π2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
πcos1(49)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
cos1(89)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B π2
2l+2mn=0(i)
and mn+nl+lm=0(ii)
From equation (i) and (ii)
(m+l)(2l+2m)+lm=0
2l2+5lm+2m2=0
2l2+4lm+lm+2m2=0
2l(l+2m)+m(l+2m)=0
(2l+m)(l+2m)=0
Direction ratios of lines are (1,2,2) and (2,1,2).
Here l1l2+m1m2+n1n2=0
Lines are perpendicular to each other.

flag
Suggest Corrections
thumbs-up
7
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Angle between Two Line Segments
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon