Question:
Write the domain and range of function $f(x)$ given by $f(x)=\sqrt{[x]-x}$.
Solution:
$f(x)=\sqrt{[x]-x}$
We know that
$[x]-x=-\{x\}$, which is the fractional part of any real number $x .$
Thus, $f(x)=\sqrt{-\{x\}}$.
Since $\{x\}$ is always a positive number, $f(x)$ is not defined for any $\mathrm{x}$.
Or $\operatorname{dom}(f)=\varphi$
Thus, range $(f)=\varphi$.