Use inverse trigonometric functions to find the solutions of the equation that are in the given interval, and approximate the solutions to four decimal places.

Question

Use inverse trigonometric functions to find the solutions of the equation that are in the given interval, and approximate the solutions to four decimal places. (Enter your answers as a comma-separated list.)

(cos x)(12 cos x + 4) = 1;     [0, 2𝜋)

x = 

Answer 1

12 cos² x + 4 cos x - 1 = 0

(2 cos x + 1)(6 cos x - 1) = 0

2 cos x = -1

cos x = -0.5

Or

6 cos x = 1

cos x = 1/6