Đáp án:
Giải thích các bước giải:
$\begin{array}{l}
DK:\left\{ \begin{array}{l}
\sqrt 3 \cot 2x + 1 \ne 0\\
\sin 2x \ne 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
\cot 2x \ne - \frac{1}{{\sqrt 3 }}\\
2x \ne k\pi
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
\cot 2x \ne \cot \left( { - \frac{\pi }{3}} \right)\\
x \ne \frac{{k\pi }}{2}
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
2x \ne - \frac{\pi }{3} + k\pi \\
x \ne \frac{{k\pi }}{2}
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
x \ne - \frac{\pi }{6} + \frac{{k\pi }}{2}\\
x \ne \frac{{k\pi }}{2}
\end{array} \right.\\
TXD:D = R\backslash \left\{ { - \frac{\pi }{6} + \frac{{k\pi }}{2};\frac{{k\pi }}{2}} \right\}
\end{array}$
