In mathematics, the running angle is the angle of consecutive vectors

(Xt,Yt)

with respect to the base line, i.e. :

\phi(t) = \arctan\left(\frac   \right) .

Usually, it is more informative to compute it using a four-quadrant version of the

arctan In mathematics, the inverse trigonometric functions (occasionally also called arcus functions, antitrigonometric functions or cyclometric functions) are the inverse functions of the trigonometric functions (with suitably restricted domains). S ...

function in a mathematical software library.

See also