Question

|A|= 5, |B|=2,, The angle between A and B is 120. Determine the unit vector in the direction of |A+B|.

I don't know what to even do. I tried but idk pls help!!

Answer 1

Since you give no indication of any directions,
without loss of generality, we can say that A = 5i
So, since A•B = -5, we can say that B = -i + bj where 1+b^2 = 2^2, so b=√3
B = -i+√3 j
Now you just need the unit vector in the direction of A+B.

Answer 2

Okk thanks alott
I found the unit vector as
1/√19|A+B|. Does that seem correct

Answer 3

yess.