There are six functions commonly used in trigonometry. Learn more about trigonometry in this article. This range will be matched against the criteria.
The triangle of most interest is the right-angled triangleThe right angle is shown by the little box in the corner.
Geometrically these are identities involving certain functions of one or more anglesThey are distinct from triangle identities which are identities potentially involving angles but also. Before getting stuck into the functions it helps to give a name to each side of a right triangle. Cot-1 x p cot-1 x. The Mathematics of the Heavens and the Earth is the first major history in English of the origins and early development of trigonometry.