Pythagorean Identitiessin2 + cos2 = 1tan2 + 1 = sec2 cot2 + 1 = csc2 Reciprocal Identities

Ratio Identities

Odd/Even Identities

sin (x) = sin xcos (x) = cos xtan (x) = tan xcsc (x) = csc xsec (x) = sec xcot (x) = cot x

Cofunction Identities, radiansCofunction Identities, degrees

sin (90 x) = cos xcos (90 x) = sin x

tan (90 x) = cot xcot (90 x) = tan x

sec (90 x) = csc xcsc (90 x) = sec x

Periodicity Identities, radiansPeriodicity Identities, degrees

sin (x + 2) = sin xcsc (x + 2) = csc xsin (x + 360) = sin xcsc (x + 360) = csc x

cos (x + 2) = cos xsec (x + 2) = sec xcos (x + 360) = cos xsec (x + 360) = sec x

tan (x + ) = tan xcot (x + ) = cot xtan (x + 180) = tan xcot (x + 180) = cot x

Sum/Difference Identities

Double Angle Identities

Half Angle Identities

orororor

Product to Sum Identities

Sum to Product Identities