Ch 03 -Trigonometric Functions

1 complete revolution = 360°

1° = 60′ and 1′ = 60″

180° = π radian

1° = π/180 rad and 1 rad = (180/π)°

Arc length l = rθ

sin x = y-coordinate of P(a,b)

cos x = x-coordinate of P(a,b)

tan x = sin x / cos x

cot x = cos x / sin x

sec x = 1 / cos x

sin(-x) = -sin x

cos(-x) = cos x

sin(π/2 - x) = cos x

cos(π/2 - x) = sin x

sin(π/2 + x) = cos x

sin^2 x + cos^2 x = 1

sec^2 x - tan^2 x = 1

cosec^2 x - cot^2 x = 1