Fundamental Trigonometric Identities Formula Sheet

Double Angle Identity: sin 2u = ?

2 sinu cosu

Double Angle Identities: cos 2u = #1?

cos²u - sin² u

Double Angle Identities: cos 2u = #2?

2cos²u - 1

Double Angle Identities: cos 2u = #3?

1 - 2 sin² u

Sum and Difference Identities:

sin (u + v) = ?

sinU cosV + cosU sinV

Sum and Difference Identities:

sin (u-v) = ?

sinU cosV - cosU sinV

Sum and Difference Identities:

cos (u+v) = ?

cosU cosV - sinU sinV

Sum and Difference Identities:

cos (u-v) = ?

cosU cosV + sinU sinV

Co-function Identities:

sin (pie/2 - u) =

cosU

Co-function Identities: tan (pie/2 - u) = ?

cotu

Co-function Identities: sec(pie/2 - u) = ?

cscU

Co-function Identities: cos(pie/2 - u) = ?

sinU

Co-function Identities: cot(pie/2 - u) = ?

tanU

Co-function Identities: csc(pie/2 - u) = ?

secU

Odd/Even Identities: sin(-u) = ?

- sin(u)

Odd/Even Identities: tan (-u) = ?

- tan(u)

Odd/Even Identities: cos(- u) = ?

cos(u)

Odd/Even Identities: sec(-u) = ?

sec(u)

Odd/Even Identities: csc(-u) = ?

- csc(u)

Odd/Even Identities: cot(-u) = ?

- cot(u)