I was asked to solve $\displaystyle \frac{x^2-x-2}{x-1}<2$ from which the solution is $\displaystyle x<0$ or $\displaystyle 1<x<3$

The next part asks: Hence solve $\displaystyle \frac{cos^22\theta-cos2\theta-2}{cos2\theta-1}<2$, where$\displaystyle 0 &\leq \theta &\leq 2\pi$

I tried doing: Replace $\displaystyle x$ with $\displaystyle cos2\theta$

$\displaystyle cos2\theta<0$ or $\displaystyle 1<cos2\theta<3$

therefore, $\displaystyle \theta<\frac{\pi}{4}$ or $\displaystyle 0<\theta<$ but $\displaystyle cos^{-1}3=$error

Can you show me the proper way to solve such an inequality? I totally forgot how to tackle this...