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

If a,b,c are three non-coplanar and p,q,r are reciprocal vectors to a,b and c respectively then (la+mb+nc).(lp+mq+nr) is equal to : (where l, m, n are scalars)

A
l2+m2+n2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
lm+mn+nl
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
0
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
none of these
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A l2+m2+n2
Given a,b,c are three non-coplanar and p,q,r are reciprocal vectors to a,b and c respectively.
ap=1,aq=0,ar=0
bp=0,bq=1,br=0
cp=0,cq=0,cr=1
Now,
(la+mb+nc).(lp+mq+nr)
=l2(ap)+lm(aq)+ln(ar)+lm(bp)+m2(bq)+mn(br)+ln(cp)+mn(cq)+n2(cr)
=l2+m2+n2
(la+mb+nc).(lp+mq+nr)=l2+m2+n2
Hence, option A.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Sum of Coefficients of All Terms
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon