trigonometric identities

RECIPROCAL: sin θ

1/cscθ

RECIPROCAL: cos θ

1/secθ

RECIPROCAL: tan θ

1/cotθ

RECIPROCAL: cotθ

1/tanθ

RECIPROCAL: cscθ

1/sinθ

RECIPROCAL: secθ

1/cosθ

PYTHAGOREAN TAN

tan²θ + 1 = sec²θ

PYTHAGOREAN SIN

sin²θ + cos²θ = 1

PYTHAGOREAN COT

cot²θ + 1 = csc²θ

SUM/DIFFERENCE SIN

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

SUM/DIFFERENCE COS

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

SUM/DIFFERENCE TAN

tan(a ± b) = (tan a ± tan b) / (1 ∓ tan a tan b)

sin(2θ)

= 2 sin θ cos θ

COS AND SIN: cos(2θ)

cos² θ - sin² θ

COS AND 1: cos(2θ)

2cos² θ - 1

SIN AND 1: cos(2θ)

1- 2sin² θ

tan(2θ)

2tanθ / (1 - tan² θ)