ĐKXĐ: \(\left\{{}\begin{matrix}\dfrac{2+sinx}{tan^2x}\ge0\left(\text{luôn đúng}\right)\\tanx\ne0\\cosx\ne0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}sinx\ne0\\cosx\ne0\end{matrix}\right.\)
\(\Rightarrow sin2x\ne0\)
\(\Rightarrow x\ne\dfrac{k\pi}{2}\)