# Thread: how to calculate the dot product ...

1. ## how to calculate the dot product ...

How to calculate the dot product of two big vectors in polar coordinate system?

2. Note that

$\mathbf{a}\cdot\mathbf{b}=ab\cos(\theta),$

where

$a=|\mathbf{a}|,\;b=|\mathbf{b}|,\;\text{and}\;\the ta$ is the angle between the two vectors. The RHS should be fairly straight-forward in polar coordinates.