ĐK $\cos x \ne 0 \Rightarrow x\ne \dfrac{\pi}{2}+k\pi;\ k \in Z$
pt $\Leftrightarrow \sin x (\dfrac{1-\cos x}{\cos x}) -\sqrt 2(\dfrac{1-\cos x}{\cos x}) +\sqrt 3 (1-\cos x)=0$
$\Leftrightarrow (1-\cos x)(\sin x -\sqrt 2 +\sqrt 3 \cos x)=0$ dễ rồi nhé