$\pi$

$\pi / 2$

$2 \pi$

$2 \pi / 3$

$f: R-Z \rightarrow[0,1]$ defined by $f(x)=\sqrt{x-[x]}$. (Here $[x]$ represents the greatest integer function)

$f: R \rightarrow(-\infty, 2)$ defined by $f(x)=4 x-x^2-3$

$f:(5, \infty) \rightarrow R-\{0\}$ defined by $f(x)=\frac{1}{\sqrt{x-5}}$

$f:[0,4] \rightarrow[0,4]$ defined by $f(x)=\sqrt{16-x^2}$

Z

$\phi$

$R-Z$

$R$

$R$

$(-\infty,-5) \cup[0,1] \cup(5, \infty)$

$(-\infty,-1] \cup(1, \infty)$

$(-\infty,-3) \cup(0,1) \cup(3, \infty)$