Trigonometric Identities

sin(a±b)

sin(a)cos(b)±cos(a)sin(b)

cos(a±b)

cos(a)cos(b)-+sin(a)sin(b)

sin(2θ)

2sin(θ)cos(θ)

cos(2θ)

cos²θ-sin²θ

cos(2θ)

1-2sin²θ

cos(2θ)

2cos²θ-1

1

cos²θ+sin²θ

sec²θ

1+tan²θ

csc²θ

1+cot²θ

sin²θ

1-cos²θ

tan²θ

sec²θ-1

cot²θ

csc²θ-1

cos²θ

1-sin²θ

-tan²θ

1-sec²θ

-cot²θ

1-csc²θ