reduction formulas
In trigonometry, the equations that express sine, cosine and tangent functions of an angle of any size in terms of the functions of an acute angle.

For example:

symbol spacesin(90° + x) = cosx
symbol spacesin(180° + x) = -sinx
symbol spacesin(270° + x) = -cosx
symbol spacecos(90° + x) = -sinx
symbol spacetan(90° + x) = -cotx

Related Term: addition formula

English | Espaņol