نكته: تابعی را كه به هر عدد صحيح $k$ خود همان عدد و به تمام اعداد بين دو عدد صحيح متوالی $k+1,k$ عدد صحيح $k$ را نسبت میدهد، تابع جزءصحيح مینامند.
نكته: تابع علامت را بهصورت زير تعريف میكنيم:
$f\left( x \right)=sign\left( x \right)=\left\{ \begin{matrix} 1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x /gt 0 \\ 0\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x=0 \\ -1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x /lt 0 \\ \end{matrix} \right.$
تابع $g,f$ را بهصورت زوج مرتب مینويسيم:
$\begin{align} & f=\left\{ \left. \left( 1,sign\left( 1 \right) \right),\left( \sqrt{2},sign\left( \sqrt{2} \right) \right),\left( \frac{1}{2},sign\left( \frac{1}{2} \right) \right),\left( -\sqrt{3},sign\left( -\sqrt{3} \right) \right) \right\} \right.\Rightarrow f=\left\{ \left. \left( 1,1 \right),\left( \sqrt{2},1 \right),\left( \frac{1}{2},1 \right),\left( -\sqrt{3},-1 \right) \right\} \right. \\ & g=\left\{ \left. \left( -\sqrt{3},\left[ -\sqrt{3} \right] \right),\left( -1,\left[ -1 \right] \right),\left( \sqrt{2},\left[ \sqrt{2} \right] \right),\left( \frac{1}{2},\left[ \frac{1}{2} \right] \right) \right\} \right.\Rightarrow g=\left\{ \left. \left( -\sqrt{3},-2 \right),\left( -1,-1 \right),\left( \sqrt{2},1 \right),\left( \frac{1}{2},0 \right) \right\} \right. \\ \end{align}$
دامنۀ تابع $\frac{f}{g}$ را حساب میكنيم:
${{D}_{\frac{f}{g}}}={{D}_{f}}\bigcap {{D}_{g}}-\left\{ \left. x\left| g\left( x \right)=0 \right. \right\} \right.=\left\{ \left. \sqrt{2},\frac{1}{2},-\sqrt{3} \right\} \right.-\left\{ \left. \frac{1}{2} \right\} \right.=\left\{ \left. \sqrt{2},-\sqrt{3} \right\} \right.$
مقدار تابع $\frac{f}{g}$ را در $x=-\sqrt{3},x=\sqrt{2}$ حساب میکنیم:
$\begin{align} & \left( \frac{f}{g} \right)\left( \sqrt{2} \right)=\frac{f\left( \sqrt{2} \right)}{g\left( \sqrt{2} \right)}=\frac{1}{1}=1\Rightarrow \left( \sqrt{2},1 \right) \\ & \left( \frac{f}{g} \right)\left( -\sqrt{3} \right)=\frac{f\left( -\sqrt{3} \right)}{g\left( -\sqrt{3} \right)}=\frac{-1}{-2}=\frac{1}{2}\Rightarrow \left( -\sqrt{3},\frac{1}{2} \right) \\ \end{align}$
پس برد تابع $\frac{f}{g}$ مجموعۀ $\left\{ \left. 1,\frac{1}{2} \right\} \right.$ است.