Trigonometric Functions

l = rθ

Radian = (π/180) × Degree

Degree = (180/π) × Radian

sin x = b, cos x = a for point P(a,b) on unit circle

sin²x + cos²x = 1

1 + tan²x = sec²x

1 + cot²x = cosec²x

tan x = sin x / cos x

cos(x+y) = cos x cos y − sin x sin y

cos(x−y) = cos x cos y + sin x sin y

sin(x+y) = sin x cos y + cos x sin y

sin(x−y) = sin x cos y − cos x sin y

tan(x+y) = (tan x + tan y) / (1 − tan x tan y)