Đáp án:
`0<x<1`
Giải thích các bước giải:
\(1-x<\sqrt{1-x}\qquad(x\le 1)\\\Leftrightarrow \sqrt{1-x}>1-x\\\Leftrightarrow \left[\begin{matrix} \sqrt{1-x}>1-x,\quad 1-x \ge 0\\ \sqrt{1-x}>1-x\quad 1-x<0\end{matrix}\right.\\\Leftrightarrow \left[\begin{matrix} 1-x>(1-x)^2,\quad -x\ge -1\\\\ x\in \mathbb{R},\quad -x<-1\end{matrix}\right.\\\Leftrightarrow \left[\begin{matrix} 0<x<1,\quad x\le 1\\\\ x\in \mathbb{R},\quad x>1\end{matrix}\right.\\\Leftrightarrow 0<x<1\)
