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If |hatAxxvecB|=sqrt(3)vecA,vecB, then t...

If `|hatAxxvecB|=sqrt(3)vecA,vecB`, then the value of `|vecA+vecB|` is :

A

`(A^(2) + B^(2) + (AB)/(sqrt3))^(1//2)`

B

`A+B`

C

`(A^(2) + B^(2) + sqrt3 AB)^(1//2)`

D

`-21hati+3hatj-5hatk`

Text Solution

Verified by Experts

The correct Answer is:
4
`|vecA xx vecB| = sqrt(3AB) rArr AB sin theta = sqrt3AB cos theta `
`rArr tan theta = sqrt3 rArr theta =60^(@)`
`R = sqrt(A^(2) + B^(2) + 2AB cos 60^(@))= (A^(2) + B^(2) +AB)^(1//2)`
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