Question

Tìm tập xác định của các hàm số sau:

1. y = \(\frac{3x+4}{x+5}\)

2. y = \(\frac{\sqrt{x-1}+\sqrt{4-x}}{\left(x-2\right)\left(x-3\right)}\)

3. y = \(\frac{3x+4}{\left(x-2\right)\left(x+4\right)}\)

4. y = \(\frac{\sqrt{2-x}}{x^2-5x+6}\)

Answer 1

ĐKXĐ:

a/ \(x+5\ne0\Rightarrow x\ne-5\)

b/ \(\left\{{}\begin{matrix}x-1\ge0\\4-x\ge0\\x-2\ne0\\x-3\ne0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}1\le x\le4\\x\ne2\\x\ne3\end{matrix}\right.\)

c/ \(\left\{{}\begin{matrix}x-2\ne0\\x+4\ne0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x\ne2\\x\ne-4\end{matrix}\right.\)

d/ \(\left\{{}\begin{matrix}2-x\ge0\\x^2-5x+6\ne0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x\le2\\x\ne2\\x\ne3\end{matrix}\right.\) \(\Rightarrow x< 2\)