Question

Find the following trigonometric values.

Express your answers exactly.
cos(150) =
sin(150) =

Answer 1

`\cos(150)\degree = -(√(3))/(2)\\`

`\sin(150)\degree=(1)/(2)\\`

Explanation:

Formulae used:

cos (180°-θ) = -cos θ

sin (80°-θ) = sin θ

Therefore,

`\cos(150)\degree = cos(180-30)\degree = -\cos(30)\degree = -(√(3))/(2) \\\\\sin(150)\degree = sin(180-30)\degree = \sin(30)\degree = (1)/(2) \\\\`