## Precalculus (6th Edition) Blitzer

If $\mathbf{v}$ and $\mathbf{w}$ are two non-zero vectors and $\theta$ is the smallest non-negative angle between them, then $\mathbf{v}\cdot \mathbf{w}=\underline{\left| \mathbf{v} \right|\left| \mathbf{w} \right|\cos \theta }$.
Dot product of two vectors is given as $\mathbf{v}\cdot \mathbf{w}=\left| \mathbf{v} \right|\left| \mathbf{w} \right|\cos \theta$ where $\theta$ is the angle between the vectors $\mathbf{v}$ and $\mathbf{w}$.