Question

Question #f358e

Answer 1

x = 180°

Explanation:

`cos^2x + 2cosx +1 = 0`
`(cosx)^2 + 2*cosx*1 + (1)^2 = 0`
`(cosx + 1)^2 = 0`
`cosx + 1 = 0`
`cosx = -1`
This is possible when x=180°

Hope it helps you