tìm tập xác định của hàm số y=sinx.tan(x+pi/4) y=cot(2x-pi/3)

`~rai~`

\(a)y=\sin x.\tan\left(x+\dfrac{\pi}{4}\right)\\ĐKXĐ:\cos\left(x+\dfrac{\pi}{4}\right)\ne 0\\\Leftrightarrow x+\dfrac{\pi}{4}\ne\dfrac{\pi}{2}+k\pi\\\Leftrightarrow x\ne\dfrac{\pi}{4}+k\pi.(k\in\mathbb{Z})\\TXĐ:D=\mathbb{R}\backslash\left\{\dfrac{\pi}{4}+k\pi\Big|k\in\mathbb{Z}\right\}.\\b)y=\cot\left(2x-\dfrac{\pi}{3}\right)\\ĐKXĐ:\sin\left(2x-\dfrac{\pi}{3}\right)\ne 0\\\Leftrightarrow 2x-\dfrac{\pi}{3}\ne k\pi\\\Leftrightarrow 2x\ne\dfrac{\pi}{3}+k\pi\\\Leftrightarrow x\ne\dfrac{\pi}{6}+k\dfrac{\pi}{2}.(k\in\mathbb{Z})\\TXĐ:D=\mathbb{R}\backslash\left\{\dfrac{\pi}{6}+k\dfrac{\pi}{2}\Big|k\in\mathbb{Z}\right\}.\)