Trigonometry Review:

Right triangle:

Theorem of Pythogoras: a² + b² = c²
(right angle between sides a and b)

sin(a) = a/c	cos(a) = b/c	tan(a) = a/b
arcsin(a/c) = a	arccos(b/c) = a	arctan(a/b) = a

note: arcsin also called sin^-1, arccos also called cos^-1, arctan also called tan^-1

General rules:

sin(2a) = 2sin(a)cos(a)
cos(2a) = cos²(a)-sin²(a)

sin(a) = cos(90° - a)
cos(a) = sin(90° - a)

sin(a ± b) = sin(a)cos(b) ± cos(a)sin(b)
cos(a ± b) = cos(a)cos(b) ± -sin(a)sin(b)

cos²(a) + sin²(a) = 1