Trigonometric Identities

Front

sin(A+B)

Back

sinAcosB+cosAsinB

Front

cos(A+B)

Back

cosAcosB-sinAsinB

Front

tan(A+B)

Back

(tanA+tanB)/(1-tanAtanB)

Front

sin(A-B)

Back

sinAcosB-cosAsinB

Front

cos(A-B)

Back

cosAcosB+sinAsinB

Front

tan(A-B)

Back

(tanA-tanB)/(1+tanAtanB)

Front

sin(x/2)

Back

-√(1-cos(x))/2

Front

cos(x/2)

Back

±√(1+cos(x))/2

Front

tan(x/2)

Back

±√((1-cosx)/(1+cosx))

Front

tan(x/2)

Back

sinx/(1+cosx)