# Length/unit vector

$|\vec{v}|=(\vec{v} \cdot \vec{v})^{1/2}$
So for any vector $\vec{v}$, you know that $\frac{\vec{v}}{|\vec{v}|}$ is a vector of unit length in the same direction as $\vec{v}$ you just multiplied it by a scalar to adjust its length to be 1.