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Let veca and vecb be unit vectors such t...

Let `veca` and `vecb` be unit vectors such that `|veca+vecb|=sqrt(3)`, then the value of `(2veca+5vecb)*(3veca+vecb+vecaxxvecb)=`

A

`11/2`

B

`13/2`

C

`39/2`

D

`23/2`

Text Solution

Verified by Experts

The correct Answer is:
C
`|veca+vecb|=sqrt(3)`
`implies1+1+2veca.vecb=3impliesveca.vecb=1/2`
Now, `(2veca+5vecb).(3veca+vecb+vecaxxvecb)`
`=6+5+17 veca.vecb=39/2`
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