What are all the exact solutions of cos x = - sqrt (3) / 2 on the interval pi < = x < = 2 pi? Give your answer in radians.

A) pi / 6 and 11 pi / 6

B) 5 pi / 6

C) 7 pi / 6

D) 5 pi / 6 and 7 pi / 6

Question

Mathematics

Dominic Fox

24 December, 13:55

What are all the exact solutions of cos x = - sqrt (3) / 2 on the interval pi < = x < = 2 pi? Give your answer in radians.

A) pi / 6 and 11 pi / 6

B) 5 pi / 6

C) 7 pi / 6

D) 5 pi / 6 and 7 pi / 6

+3

Answers (1)

Know the Answer?

Lilia · Answer 1

Interval: pi < = x < = 2pi OR 180< = x < = 360

This means the interval must be between Quadrants 3/4

pi/6 = 30 degrees which is < 180

5pi/6 = 150 degrees which is < 180

7pi/6 = last option but = 210 degrees which is in Q3

cos (7pi/6) = - sqrt (3) / 2

Ans: C

What are all the exact solutions of cos x = - sqrt (3) / 2 on the interval pi < = x < = 2 pi? Give your answer in radians.A) pi / 6 and 11 pi / 6B) 5 pi / 6C) 7 pi / 6D) 5 pi / 6 and 7 pi / 6

What are all the exact solutions of cos x = - sqrt (3) / 2 on the interval pi < = x < = 2 pi? Give your answer in radians.

A) pi / 6 and 11 pi / 6

B) 5 pi / 6

C) 7 pi / 6

D) 5 pi / 6 and 7 pi / 6