\(\vec{v} =\left(\begin{array}{c}x\\y\end{array}\right)=(x,y)\)
\(\vec{AB}=\left(\begin{array}{c}{x_{a}-x_{b}}\\y_{a}-y_{b}\end{array}\right)=\left(\begin{array}{c}x\\y\end{array}\right)\)
\(|\vec{AB}|=\sqrt{{x^2}+{y^2}}\)
I matematik programmer benyttes ofte kommando’en \(Norm(\vec{a})\) til at bestemme længden
\(\hat{v} = \frac{\vec{v}}{|{\vec{v}|}\)
Referencer:
http://en.wikipedia.org/wiki/Unit_vector
http://mathworld.wolfram.com/UnitVector.html