Question

How do you solve `4cos^(2)x=1`?

Answer 1

I would take the `4` to the right:
`cos^2(x)=1/4`
take the square root of both sides:
`cos(x)=+-1/2`
So you get that:

if `cos(x)=1/2`
`x=pi/3+2npi`
and:
`x=5pi/3+2npi`

if `cos(x)=-1/2`
`x=2pi/3+2npi`
and:
`x=4pi/3+2npi`

[`n=0,1,2,3,....`]