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

Solution for cos(2x)+cos(x)+1=0 equation:

Simplifying
cos(2x) + cos(x) + 1 = 0

Remove parenthesis around (2x)
cos * 2x + cos(x) + 1 = 0

Reorder the terms for easier multiplication:
2cos * x + cos(x) + 1 = 0

Multiply cos * x
2cosx + cos(x) + 1 = 0

Multiply cos * x
2cosx + cosx + 1 = 0

Reorder the terms:
1 + 2cosx + cosx = 0

Combine like terms: 2cosx + cosx = 3cosx
1 + 3cosx = 0

Solving
1 + 3cosx = 0

Solving for variable 'c'.

Move all terms containing c to the left, all other terms to the right.

Add '-1' to each side of the equation.
1 + -1 + 3cosx = 0 + -1

Combine like terms: 1 + -1 = 0
0 + 3cosx = 0 + -1
3cosx = 0 + -1

Combine like terms: 0 + -1 = -1
3cosx = -1

Divide each side by '3osx'.
c = -0.3333333333o-1s-1x-1

Simplifying
c = -0.3333333333o-1s-1x-1