cosx*(4cosx)-1=0

Solution for cosx*(4cosx)-1=0 equation:

Simplifying
cosx(4cosx) + -1 = 0

Remove parenthesis around (4cosx)
cosx * 4cosx + -1 = 0

Reorder the terms for easier multiplication:
4cosx * cosx + -1 = 0

Multiply cosx * cosx
4c2o2s2x2 + -1 = 0

Reorder the terms:
-1 + 4c2o2s2x2 = 0

Solving
-1 + 4c2o2s2x2 = 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 + 4c2o2s2x2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + 4c2o2s2x2 = 0 + 1
4c2o2s2x2 = 0 + 1

Combine like terms: 0 + 1 = 1
4c2o2s2x2 = 1

Divide each side by '4o2s2x2'.
c2 = 0.25o-2s-2x-2

Simplifying
c2 = 0.25o-2s-2x-2

Take the square root of each side:
c = {-0.5o-1s-1x-1, 0.5o-1s-1x-1}