Question

Find all solutions of the equation in the interval [0, 2π).

2 cos²x+cosx-1=0
Write your answer in radians in terms of .
If there is more than one solution, separate them with commas.

Answer 1

Sorry I don’t know I just need to answer a question so I can ask one sorry

Answer 2

Explanation:

This is a quadratic and needs to be factored as such. When we factor, we get

cosx = 1/2 and cosx = -1. Refer to the unit circle to find all the angles that have a cosine of 1/2. Those would be in Q1 and Q4; namely, pi/3 and 5pi/3. The angle where the cosine is -1 is at pi.

`x=\pi ,(\pi )/(3),(5\pi )/(3)`