% X. Rendtel
% Letzte Aenderung:

\documentclass[10pt, a4paper]{article}
\usepackage[utf8x]{inputenc}
\usepackage[tight]{units}
\usepackage{euler}
\usepackage{calc}
\usepackage{pstricks}
\usepackage{rotating}

\usepackage{pst-pdf}
\usepackage{pst-node}

\usepackage{xcolor}
\usepackage{graphicx}
%\usepackage{multido}
\usepackage{pst-circ}
\usepackage{pst-func}
\usepackage{pst-math}

\usepackage{pst-eucl}
\usepackage{fancyhdr}
\pagestyle{fancyplain}

\usepackage{pstricks-add}
\usepackage[greek,german]{babel}

\usepackage{pst-tree}








\thispagestyle{empty}
\pagestyle{empty}

%\SpecialCoor

\usepackage[LGR,T1]{fontenc}
\usepackage{mathpazo,avant,courier}
\newcommand{\EUR}{\textgreek{\euro}}

\makeatletter
\newcommand{\psxpoint}[3][black]{%
  \psline[linewidth=.5pt]{-}(#2,\pst@xticksizeB)(#2,\pst@xticksizeA)
  \rput[t](! #2 \pst@number\pslabelsep \pst@number\pst@xticksizeB add
	\pst@number\psyunit div neg ){\color{#1}#3}}
\makeatother


\makeatletter
\newcommand{\psypoint}[3][black]{%
  \psline[linewidth=.5pt]{-}(\pst@yticksizeB,#2)(\pst@yticksizeA,#2)
  \rput[r](! \pst@number\pslabelsep \pst@number\pst@yticksizeA sub
	\pst@number\psxunit div neg #2){\color{#1}#3}}
\makeatother

\def\myLine#1(#2)(#3)#4{{%
  \pnode(#2){myA}\pnode(#3){myB}%
  \pcline[linestyle=dashed,tbarsize=15pt]{#1}(myA)(myB)%
  \ncput*{#4}}}



\newcommand{\knoten}[2][white]
{\Tr{\psframebox[fillcolor=#1!50,fillstyle=solid]{#2}}}

\begin{document}
\psset{xunit=1cm,yunit=1cm,dotstyle=*,dotsize=3pt
0,linewidth=0.8pt,arrowsize=3pt 2,arrowinset=0.25}

\psset{xunit=1.0cm,yunit=1.0cm,algebraic=true,dotstyle=*,dotsize=3pt 0,linewidth=0.8pt,arrowsize=3pt 2,arrowinset=0.25}
\psset{xunit=1cm,yunit=1cm,algebraic=true}
\psset{xunit=1cm,yunit=1cm,algebraic=true}
\begin{pspicture}(-5.2,-4)(6,4) 



\rput[l]{0}(-0.3,1){\color{red}{\Large $b$}}
\rput[l]{0}(3,-0.3){\color{red}{\Large $a$}}


\psaxes[comma,Dx=10,Dy=10,dx=0pt,dy=0pt,Ox=0,Oy=0,showorigin=false]{->}(0,0)(-4.2,-3)(5,3)
\uput[-90](5,0){$x$}
 \uput[0](0,3){$y$}


\psellipse[linewidth=1.5pt,linecolor=red](0,0)(4,2)


\psframe[fillcolor=white,fillstyle=solid](-0.25,-2)(0.25,-1) 
\psframe[fillcolor=white,fillstyle=solid](0.822,-0.25)(1.822,+0.25) 
\psline[arrowsize=5pt,linecolor=blue,linewidth=1.2pt]{<->}(0.822,0.4)(1.822,0.4) 
\psline[arrowsize=5pt,linecolor=blue,linewidth=1.2pt]{<->}(-0.4,-2)(-0.4,-1) 


\cnode*(0,-1.5){2pt}{A} 
\cnode*(2.6457,1.5){2pt}{B} 
\cnode*(1.322,0){2pt}{C} 


\pcline[offset=-5pt]{|<->|}(A)(B)\lput*{:U}{$a$} 
\pcline[offset=5pt]{|<->|}(C)(B)\lput*{:U}{$b$} 


\pcline{-}(A)(B) 


\psframe[](0.822,-0.25)(1.822,+0.25) 
\cnode*(1.322,0){2pt}{D} 
\end{pspicture}


\end{document}
