Pt $\Leftrightarrow (cos^{2}x + sin^{2}x)(cos^{2}x - sin^{2}x)+\sqrt{3}sin2x =1$$\Leftrightarrow cos2x + \sqrt{3}sin2x =1$
$\Leftrightarrow \frac{1}{2}cos2x + \frac{\sqrt{3}}{2}sin2x = \frac{1}{2}$
$\Leftrightarrow cos (2x -\frac{\pi }{3}) = cos\frac{\pi }{3} $
$\Leftrightarrow 2x - \frac{\pi }{3}= \pm \frac{\pi }{3} + k2\pi $
$\Leftrightarrow x=\frac{\pi }{3} + k\pi , x= k\pi ,( k\in Z )$