Tập xác định D của hàm số y = 3 cos x /(2 sin x − 1) .

4/19

Tập xác định \[D\] của hàm số \[y = \frac{{3\cos x}}{{2\sin x - 1}}\].

\[D = \mathbb{R}\backslash \left\{ {\frac{{5\pi }}{6} + k2\pi \,;\,\,\frac{\pi }{6} + k2\pi ,k \in \mathbb{Z}} \right\}\].

\[D = \mathbb{R}\backslash \left\{ {\frac{\pi }{6} + k2\pi ,k \in \mathbb{Z}} \right\}\].

\[D = \mathbb{R}\].

\[D = \mathbb{R}\backslash \left\{ {\frac{1}{2}} \right\}\].

Giải thích

Chọn A

ĐK: \[2\sin x - 1 \ne 0\] \[ \Leftrightarrow \sin x \ne \frac{1}{2}\] \[ \Leftrightarrow \sin x \ne \sin \frac{\pi }{6}\] \[ \Leftrightarrow \left\{ \begin{array}{l}x \ne \frac{\pi }{6} + k2\pi \\x \ne \frac{{5\pi }}{6} + k2\pi \end{array} \right.,k \in \mathbb{Z}\].

TXĐ: \[D = \mathbb{R}\backslash \left\{ {\frac{{5\pi }}{6} + k2\pi \,;\,\,\frac{\pi }{6} + k2\pi ,k \in \mathbb{Z}} \right\}\].