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Let bara barb barc be three unit vectors...

Let `bara barb barc` be three unit vectors such that `|bara+barb+barc|`=1 and `barc` makes angles a and b with `bara and barb` respectively then `cosa+cosb` is equal to

A

`3//2`

B

1

C

-1

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
C
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