Trigonometry

Formulas

sin(x+y)

sin(x+y)

sinx cosy + cosx siny

sin (x-y)

sinx cosy - cosx siny

cos (x-y)

cosx cosy - sinx siny

cos (x+y)

cosx cosy - sinx siny

tan (x + y)

tanx +tan y ÷ 1- tanx tany

tan (x-y)

tanx-tany ÷ 1+tanx tany

cot(x+y)

cotx coty-1 ÷ coty+cotx

cot (x-y)

cotx coty+1 ÷ coty - cotx

1 cos2x

cos²x-sin²x

2 cos2x

2cos²x - 1

3 cos2x

1 - 2sin² x

4 cos2x

1- tan²x ÷ 1+ tan²x

1 sin2x

2sinx cosx

2 sin2x

2tanx ÷ 1+ tan² x

tan 2x

2tanx ÷ 1+ tan²x

sin 3x

3 sinx - 4 sin³x

cos 3x

4 cos³x - 3 cos x

tan 3x

3tanx - tan³ x ÷ 1- 3tan²x

1 + cos 2x

2 cos²x

1 - cos 2x

2 sin²x

cosx + cos y

2cos(x+y/2) cos(x-y/2)

cosx- cosy

-2sin(x+y/2) sin(x-y/2)

Sinx + siny

2sin(x+y/2) cos(x-y/2)

sinx - siny

2cos(x+y/2) sin(x-y/2)