# How do I find the resultant of vectors?

If A and B are two vectors with an angle between them equal to $\theta$ ($\theta < \pi$), their resultant R is given by,
$R = {\left[{A}^{2} + {B}^{2} + 2 A B C o s \theta\right]}^{\frac{1}{2}}$, this gives the magnitude of R.
If the vector R makes an angle $\alpha$ with vector A, then
$\alpha = \arctan \left[\frac{B C o s \theta}{A + B S \in \theta}\right]$