wiz-icon
MyQuestionIcon
MyQuestionIcon
7
You visited us 7 times! Enjoying our articles? Unlock Full Access!
Question

If a, b, c are non-coplanar vectors and ^d is a unit vector, then the value of (a.^d)(b×c)+(b.^d)(c×a)+(c.^d)(a×b) is equal to

A
1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
[abc]
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
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 C [abc]
Since a,b,c are non-coplanar, a×b,b×c,c×a are also non-coplanar, d can be expressed uniquely in terms of a,b and c.
Suppose d=x(b×c)+y(c×a)+x(a×b)
Then a.d=x[abc],b.d=y[abc],c.d=z[abc]
|(a.d)(b×c)+(b.d)(c×a)+(c.d)(a×b)|=|[abc][x(b×c)+y(c×a)+x(a×b)]|=|[abc]d|=|[abc]|×1=|[abc]|

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Vector Product
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon