Answer:
Step-by-step explanation:
2π/3 radians is equivalent to
2π 180°
-------- * ---------- = 120°
3 π rad
This angle (120°) is 30° past 90°. The 'opposite side' of the triangle formed by this ray of length 1 is √3 and the 'adjacent side' is 1.
adj side -1
cos 120° is in Quadrant II. cos 120° = --------------- = ---------
hyp 2
√3
and sin 120° = --------
2
