Trig Identities

Quotient Trig Identity (Tan)

sin Θ/cosΘ

Quotient Trig Identity (cot)

cos Θ/sin Θ

Pythagorean Trig Identities (sin)

sin²x+cos²x=1

Pythagorean Trig Identities (tan/cot)

1+cot²x=csc²x

tan²x+1=sec²x

cot²x=csc²x-1

tan²x=sec²x-1

sin (u±v)

sin u cos v ± cos u sin v

cos (u±v)

cos u cos v ∓ sin u sin v

tan (u±v)

tan u ± tan v/ 1 ∓ tan u tan v

Double Angles (Sin)

sin (2u)= 2 sin u cos u

Double Angles (tan)

tan (2u) = 2 tan u/1-tan²u

Double Angles (cos)

cos (2u)= cos²u-sin²u

= 2cos²u-1

= 1-2sin²u

sin (-u)

-sin u

cos (-u)

cos u

tan (-u)

-tan u

csc (-u)

-csc u

sec (-u)

sec u

cot (-u)

-cot u

sin (π/2-u)

cos u

cos (π/2-u)

sin u

tan (π/2-u)

cot u

csc (π/2-u)

sec (u)

sec (π/2-u)

csc (u)

cot (π/2-u)

tan u