express cos330 as its cofunction. Find the exact value of this function.

Question

can someone people SHOW me how to get the answer.

Answer 1

The cofunction of the cosine is the sine.

 

cos θ = sin (90° - θ)

cos 330° = sin (90° - 330°)

cos 330° = sin -240°

cos 330° = sin 120° 

Answer 2

Its cofunction will be sin(360 - 330) = sin30

 

sin30 = -√(3) / 2

 

Since the 30 degrees is in the 4th quadrant, the value of sin30 will be negative.