Some trig identities

Pythagrean

Sin²x + Cos²x =1

Double angle (sin)

Sin2x = 2SinxCosx

Double angle (cos)

Cos2x = Cos^2x-Sin^2x

Sum / Difference (sin)

Sin(x +- y) = SinxCosy +- CosxSiny

Sum / Difference (cos)

Cos(x +- y) = CosxCosy -+ SinxSiny

“Invertible”

Passes horizontal line test

Tan Period

pi

Parent Function of any trig equation

Atrig(B(x-C))+D

Sec

1/Cos

Csc

1/sin

Cot

Cos/Sin

Period of sin and cosine

2pi

Period of Sec and Csc

2pi

Period of Cot

pi