Question

tìm tập nghiệm xác định các biểu thức

1, \(\frac{1}{\sqrt{x^2+x-2}}\) 2, \(2-\sqrt{1-4x^2}\) 3, \(\frac{1}{\sqrt{3x-2}}\) 4, \(\sqrt{\left(x+2\right)\left(x-3\right)}\)

Answer 1

ĐKXĐ:

a/ \(x^2+x-2>0\Rightarrow\left[{}\begin{matrix}x< -2\\x>1\end{matrix}\right.\)

\(D=\left(-\infty;-2\right)\cup\left(1;+\infty\right)\)

b/ \(1-4x^2\ge0\Rightarrow x^2\le\frac{1}{4}\Rightarrow-\frac{1}{2}\le x\le2\)

\(D=\left[-\frac{1}{2};\frac{1}{2}\right]\)

c/ \(3x-2>0\Rightarrow x>\frac{2}{3}\)

\(D=\left(\frac{2}{3};+\infty\right)\)

d/ \(\left(x+2\right)\left(x-3\right)\ge0\Rightarrow\left[{}\begin{matrix}x\le-2\\x\ge3\end{matrix}\right.\)

\(D=(-\infty;-2]\cup[3;+\infty)\)