Question

Use the unit circle to find the inverse function value in degrees.

 

cos-1(sqrt3/2)

	A. 60°
	B. 30°
	C. 240°

D. 150

 

Answer 1

Given that

The answer is option (b)

Answer 2

the unit circle can help you find the correct quadrants, but you have to memorize the actual degrees. You should know the sin, cos and tan of 0º, 30º, 45º, 60º, and 90º

These are the values you should remember!

Angle	Sin	Cos	Tan=Sin/Cos
30°			1/√3 = √3/3
45°			1
60°			√3

 

From table cos30° =

so, the value of the given inverse function is 30°