[tex]sin^{2}x + cos2x - \frac{1}{4} = 0[/tex]
[tex]sin^{2}x + cos^{2}x - sin^{2}x = \frac{1}{4}[/tex]
[tex]cos^{2}x = \frac{1}{4}[/tex]
[tex]cos(x) = \pm \frac{1}{2}[/tex]
[tex]x = \pm \frac{\pi}{3}[/tex]
General solutions: [tex]x = \pi(n - \frac{1}{3})[/tex] and [tex]x = \pi(n + \frac{1}{3})[/tex]