Precalculus Trigonometric Identities

sin x → csc

1/csc x

csc x → sin

1/sin x

cos x → sec

1/sec x

sec x → cos

1/cos x

tan x → cot

1/cot x

tan x → sin

sin x / cos x

cot x → tan

1/tan x

cot x → cos

cos x / sin x

arccos x

arcsin √1-x²

arcsin x

arccos √1-x²

sin (a + b)

sin a cos b + cos a sin b

cos (a+b)

cos a cos b - sin a sin b

sin(2Θ)

2sinΘcosΘ

cos(2Θ)

cos²Θ - sin²Θ , 1- 2sin²Θ , 2cos²Θ -1