Question

the resultant Ċ of A and B is perpendicular
to A. Also, AHC). The angle between Ā
and B is :
​

Answer 1

Answer:

If C=A+b

and C is perpendicular to A

C . A =0

(A+b).A =0

if 0 is the angle between a and b

A2 + ABcos (0)= 0

0= cos -1 (-A\B)

using triangle law of cosines to present |C| in

terms of |A| and |B|

C2 =A2+B2 - 2 ABcos (0)

now we also know

|C| =| A|

A2= A2+B2 - 2Abcos (0)

0= cos -1 (B/2A).

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