Trig Identities

Sum and Difference Identities

sin (u+v) = sinucosv + cosusinv

sin (u-v)

Double Angle Identities

sin 2u = 2sinucosu

cos 2u = cos²u-sin²u or 1-2sin²u or 2cos²u-1

tan 2u = 2tanu/1-tan²u

Power Reducing Identities

sin²u = (1-cos2u)/2

cos²u = (1+cos2u)/2

tan²u = (1-cos2u)/(1+cos2u)

Half Angle Identities

sin u/2 = +- rad ((1-cosu)/2)

cos u/2 = +