\begin{exercice}\label{2G6_E_avecprop3e}Donner un réel associé au point $A$.
\vspace{-0.5em}
 \begin{tikzpicture}[general,scale=1.71]
  \draw (0,0) circle (1);
  \draw[dashed] (1,0)--(-1,0);
  \draw[dashed] (0,1)--(0,-1);
  \draw[dashed] (0,1)--(-1,1);
  \draw [color=F1] (1,0)-- (0,1);
  \draw [color=F1] (0,0)-- (-1,1);
  \draw[color=A1] (0.5,0) node[ rotate=90] {{\boldmath $\approx$}};
  \draw[color=A1] (0,0.5) node {{\boldmath $\approx$}};
  \draw[color=A1] (-0.5,1) node[ rotate=90] {{\boldmath $\approx$}};
  \draw[color=C1] (0.5,0.5) node[rotate=45] {{\boldmath$\infty$}};
  \draw[color=C1] (-0.5,0.5) node[rotate=45] {{\boldmath$\infty$}};
  \draw (0,1) node[above] {$B$};
  \draw (-0.71,0.71) node[left] {$A$};
  \draw (-1,1) node[left] {$D$};
  \draw (1,0) node[right] {$C$};
  \draw(-0.1,-0.2) node {$O$};
 \end{tikzpicture}
\hfill
 \begin{tikzpicture}[general,scale=1.71]
 \draw (0,0) circle (1);
  \draw[dashed] (1,0)--(-1,0);
  \draw[dashed] (0,1)--(0,-1);
  \draw (0.5,0.87)--(0,0);
  \draw[color=F1] (0.425,1)--(1.11,-0.2);
  \draw[color=C1] (0.25,0.435) node[ rotate=-30] {{\boldmath $\approx$}};
  \draw[color=C1] (0.75,0.435) node[ rotate=30] {{\boldmath $\approx$}};
  \draw[color=C1] (0.5,0) node[ rotate=90] {{\boldmath $\approx$}};
  \draw (0.5,0.87) node[above right] {$B$};
  \draw (-0.5,0.87) node[above left] {$A$};
  \draw (1,0) node[below left] {$C$};
  \draw (0,1) node[above] {$\phantom{B}$};
  \draw[color=F1] (0.5,-0.87)--(-0.5,0.87);
  \draw(-0.1,-0.2) node {$O$};
 \end{tikzpicture}
  \textit{Les droites de la même couleur sont parallèles.}
 \end{exercice}

