Question

Find the degree measures of the angle whose cosine is −√3/2.

A. 50° + n times 360° and 30° + n times 360
B. 120 +n times 360 and 60 + n times 360
C. 120+n times 360 and 240 +n times 360
D. 150+n times 360 and 210 +n times 360

Answer 1

given that the cosine of an angle is −√3/2, to solve the value of the angle. use the function inverse cosine or arccosine. so the value of the angle
A = arccosine ( −√3/2 )
A = 150 degrees
so the answer is D.
150 +n times 360 and 210 +n times 360