Download the app

Questions  

 If a,b,c are three non-coplanar and p,q,r are reciprocal vectors to a,b and c respectively, then la+mb+nclp+mq+nr is equal to : (where 1,m,n_ are scalars) 

Remember concepts with our Masterclasses.

80k Users
60 mins Expert Faculty Ask Questions
a
l2 + m2 + n2
b
lm+mn+nl
c
0
d
None of these

Ready to Test Your Skills?

Check Your Performance Today with our Free Mock Tests used by Toppers!

detailed solution

Correct option is A

p→   =  b→ × c→a→   b→   c→  ;  q→  =  c→ × a→a→   b→   c→ ;  r→  = a→ × b→a→   b→   c→a→.p→=a→·  b→ × c→a→   b→   c→=a→   b→   c→a→   b→   c→=1    and a→.q→=a→·  c→ × a→a→   b→   c→=a→   c→   a→a→   b→   c→=0similarly b→·q→ =1  c→·r→=1 la→+mb→+nc→⋅lp→+mq→+nr→ =l2a→·p→ +m2b→.q→+n2c→·r→  =l2+m2+n2


Similar Questions

  Let V=2i^+j^k^ and W=i^+3k^. If U is a unit vector, then the maximum value of the scalar triple product[UVW] is 


whats app icon
phone icon