Question

find the value of cos (570°)​

Answer 1

Answer:

=>cos(570°)

=>cos(360°+210°) [ it again repeat the angle 210°]

so, cos(210°)

=> cos(180°+30°) [ it is in 3rd quadrant and cosθ

negative in 3rd quadrant]

so, -cos(30°)

=> -√3/2 (answer)