PlanetPhysics/Dot Product

The dot product or scalar product is defined as

$\mathbf {A} \cdot \mathbf {B} =A_{x}B_{x}+A_{y}B_{y}+A_{z}B_{z}$

{\mathbf Geometric interpretation}

Using a geometric interpretation allows us to find the angle between two vectors because

$\mathbf {A} \cdot \mathbf {B} =\left|\mathbf {A} \right|\left|\mathbf {B} \right|\cos \theta$

It is also useful to note that if the two vectors are perpindicular, their dot product is zero since

$\cos \left(90^{o}\right)=0$