Trigonometric Identities

reciprocal identity

sin θ

1/csc θ

reciprocal identity

cos θ

1/sec θ

reciprocal identity

tan θ

1/cot θ

reciprocal identity

sec θ

1/cos θ

reciprocal identity

csc θ

1/sin θ

reciprocal identity

cot θ

1/tan θ

pythagorean identity

sin^2 x + cos^2 x

1

pythagorean identity

1-sin² x

cos²x

pythagorean identity

sec² x -1

tan² x

pythagorean identity

csc² x -1

cot² x

pythagorean identity

1 + tan² x

sec² x

pythagorean identity

1 + cot² x

csc² x

quotient identity

tan θ

sin θ/cos θ

quotient identity

cot θ

cos θ/sin θ

sin x cos x

1/2 sin 2x

sin² x

1/2 (1 - cos 2x)

cos² x

1/2 (1 + cos 2x)

sin A sin B

1/2 [ cos (A - B) - cos (A + B)]

cos A cos B

1/2 [cos (A - B) + cos (A + B)]

sin A cos B

1/2 [sin (A - B) + sin (A + B)]

sin 2x

2 sin x cos x

cos 2x

cos² x - sin² x

cos 2x

2cos² x - 1

cos 2x

1 - 2 sin² x

tan 2x

2 tan x / 1 - tan² x