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

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

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

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

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

Reorder the terms for easier multiplication:
-1 = cosx + 2cos * x

Multiply cos * x
-1 = cosx + 2cosx

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

Solving
-1 = 3cosx

Solving for variable 'c'.

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

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

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

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