Angle

Definition: Angle

The angle between two nonzero vectors $\mathbf{u}$ and $\mathbf{v}$ of an inner product space is

$$\arccos \left(\frac{⟨\mathbf{u},\mathbf{v}⟩}{||\mathbf{u}||||\mathbf{v}||}\right)$$

NOTATION

$$\angle (\mathbf{u},\mathbf{v})$$