Find all possiblie values of \(\cos(\theta)\) if \( \cos(2\theta) = 2\cos(\theta) .\)
I am pretty sure I saw this question answered yesterday. Go see if you can find it.
Hint:
cos(2x)=cos^2x-sin^2x
and
sin^2x=1-cos^2x
simplify then sub y=cos(theta)
then solve as a quadratic
