2cot (2x - pi/3) + 1 tìm TXĐ ??? giúp em với ạ

Đáp án:

$\begin{array}{l}
2\cot \left( {2x - \frac{\pi }{3}} \right) + 1\\
Xác\,định \Leftrightarrow \sin \left( {2x - \frac{\pi }{3}} \right) \ne 0\\
 \Rightarrow 2x - \frac{\pi }{3} \ne k\pi \left( {k \in Z} \right)\\
 \Rightarrow 2x \ne \frac{\pi }{3} + k\pi \left( {k \in Z} \right)\\
 \Rightarrow x \ne \frac{\pi }{6} + \frac{{k\pi }}{2}\left( {k \in Z} \right)
\end{array}$

ĐK: $\sin(2x-\dfrac{\pi}{3})\ne 0$

$\Leftrightarrow 2x-\dfrac{\pi}{3}\ne k\pi$

$\Leftrightarrow x\ne\dfrac{\pi}{6}+\dfrac{k\pi}{2}$

$\to D=\mathbb{R}$ \ $\{\dfrac{\pi}{6}+\dfrac{k\pi}{2}\}$