\ANG{
%%\item
Gib, wenn m"oglich, zu den abgebildeten Graphen einen Funktionsterm und 
einen passenden Definitionsbereich an.
Begr"unde andernfalls, warum der Graph keine Funktion darstellt.

$$
\beginpicture
\setcoordinatesystem units <0.8mm,0.8mm> %point at 0 -75

\put{\beginpicture
  %\setcoordinatesystem units <1mm,1mm> point at -20 0
  \setplotarea x from -25  to 25, y from -25 to 25
  \setdots <1mm>
  \grid 10 10
  \put {(a)} at -15 23
  \setsolid
  \arrow <3mm> [0.4,0.8] from 0 0 to   0  25
  \arrow <3mm> [0.4,0.8] from 0 0 to  25   0
  \plot  -25   0  0  0 /
  \plot    0 -25  0  0 /
  \setlinear 
  \plot 10 -2 10  2  /
  \plot -2 10  2 10  /
  \multiput {1} at 10 3 3 10  /
  \setlinear
  \setplotsymbol({\circle*{2}} [Bl])
  \plot  -25  25  0  0 -25 -25 /
  \endpicture} at 0  25
\put{\beginpicture
  %\setcoordinatesystem units <1mm,1mm> point at -20 0
  \setplotarea x from -25  to 25, y from -25 to 25
  \setdots <1mm>
  \grid 10 10
  \put {(b)} at -15 23
  \setsolid
  \arrow <3mm> [0.4,0.8] from 0 0 to   0  25
  \arrow <3mm> [0.4,0.8] from 0 0 to  25   0
  \plot  -25   0  0  0 /
  \plot    0 -25  0  0 /
  \setlinear 
  \plot 10 -2 10  2  /
  \plot -2 10  2 10  /
  \multiput {1} at 10 3 3 10  /
  \setlinear
  \setplotsymbol({\circle*{2}} [Bl])
  \plot  -25   0  0  0  12.5 25 /
  \endpicture} at 55  25
\put{\beginpicture
  %\setcoordinatesystem units <1mm,1mm> point at -20 0
  \setplotarea x from -25  to 25, y from -25 to 25
  \setdots <1mm>
  \grid 10 10
  \put {(c)} at -15 23
  \setsolid
  \arrow <3mm> [0.4,0.8] from 0 0 to   0  25
  \arrow <3mm> [0.4,0.8] from 0 0 to  25   0
  \plot  -25   0  0  0 /
  \plot    0 -25  0  0 /
  \setlinear 
  \plot 10 -2 10  2  /
  \plot -2 10  2 10  /
  \multiput {1} at 10 3 3 10  /
  \setlinear
  \setplotsymbol({\circle*{2}} [Bl])
  \multiput {\circle*{3}}[Bl] at -20 10   -10 5    0   0
                              10  -5    20 -10   /
  \endpicture} at 110  25
\endpicture
$$

}
\LSG{
(a) Kein Funktionsgraph, da z. B. f"ur $x=-1$ kein eindeutiger Funktionswert existiert. \\
(b)  $\DD= \QQ$ und $f(x)=x+|x|$ \\
(c) $\DD=\ZZ$ und $f(x)=-0,5x$
}


