Đáp án:
$TXD: D = R\backslash \left\{-\dfrac{\pi}{3} + k\pi\left|\, k\in \Bbb Z\right.\right\}$
Giải thích các bước giải:
$y = \dfrac{1}{\sin\left(x + \dfrac{\pi}{3}\right)}$
$y$ xác định $\Leftrightarrow \sin\left(x + \dfrac{\pi}{3}\right) \ne 0$
$\Leftrightarrow x + \dfrac{\pi}{3} \ne k\pi$
$\Leftrightarrow x \ne -\dfrac{\pi}{3} + k\pi$
$\Rightarrow TXD: D = R\backslash \left\{-\dfrac{\pi}{3} + k\pi\left|\, k\in \Bbb Z\right.\right\}$
