- #1

lovemake1

- 149

- 1

## Homework Statement

solve the following equations or inequalties for x in the interval [0,2pi)

2cos^2(x) + 1 = 3cos(2x)

## Homework Equations

## The Attempt at a Solution

My attempt at the problem:

2cosx(cos2x) + 1 = 3cos(2x)

2cosx(cos^2x - sin^2x) + 1 = 3cos(2x)

2cos^3x - 2cosxsin^2x + 1 = 3(1-2sin^2x)

2cos^3x - 2cosxsin^2x + 1 = 3-6sin^2x

2cos^3x - 2cosxsin^2x + 1 - 3 + 6sin^2x = 0

and I am getting lost here...

please help,