[tex]DK:sin2x\neq 0\Leftrightarrow x\neq k\frac{\pi}{2}[/tex]
[tex]PT\Leftrightarrow \frac{2021sin^2x+cos^2x}{sinxcosx}=2020\sqrt{3}+\frac{1}{sinxcosx}\\\Leftrightarrow \frac{2020sin^2x+1}{sinxcosx}=2020\sqrt{3}+\frac{1}{sinxcosx}\\\Leftrightarrow \frac{2020sin^2x}{sinxcosx}=2020\sqrt{3}\\\Leftrightarrow 2020tanx=2020\sqrt{3}\\\Leftrightarrow tanx=\sqrt{3}\\\Leftrightarrow ...[/tex]