# How do you solve the following equation #cos2x+cosx=0# in the interval [0, 2pi]?

##### 1 Answer

Jul 4, 2016

#### Answer:

I found:

#### Explanation:

We can use trigonometric identities to change all into

and:

We can solve this using the Quadratic Formula as in a second degree equation in

we can write

and we get:

but: