Question

What are the coordinates of the terminal point determined by t=20pi/3?

Answer 1

(- 1/2 , √3/2)

Explanation:

t=20π/3

t' = 20π/3 - 6π = 2π/3 (120°) ... 2nd quadrant

If we start from (1,0) of unit circle, the coordinate of terminal point (x,y)

OF/OE = - cos 60° = x / 1 = - 1/2

FE/OE = sin 60° = y/1 = √3/2