see this article for its expression in terms of Euler angles.
Leonhard Euler | Euler | Angles | Euler characteristic | Euler Hermes | Euler's totient function | Euler–Maclaurin formula | Euler diagram | Angles (The Strokes album) | kings of the Angles | Euler's three-body problem | Euler's theorem | Euler's_rotation_theorem | Euler number | Euler method | Euler D.I | Euler Book Prize | Euler angles | Cauchy–Euler equation | An illustration of a complex number plotted on the complex plane using Euler's formula | Angles-sur-l'Anglin | AMS Euler |
The Toolbox provides functions for manipulating and converting between datatypes such as: vectors;homogeneous transformations; roll-pitch-yaw and Euler angles and unit-quaternions which are necessary to represent 3-dimensional position and orientation.