\begin{exercice}\label{2G6_lireabscurv}
Donner un réel associé à chaque point du cercle.
 
 \begin{tikzpicture}[general,scale=1.71]
  \draw (0,0) circle (1);
  \draw (0.87,0.5)--(-0.87,-0.5);
  \draw (-0.87,0.5)--(0.87,-0.5);
  \draw[dashed] (0,1)--(0,-1);
  \draw[dashed] (1,0)--(-1,0);
  \draw[color=F1] (0.3,0) arc (0:30:0.3);
  \draw[color=F1] (0.4,0) arc (0:30:0.4);
  \draw[color=F1] (-0.3,0) arc (180:150:0.3);
  \draw[color=F1] (-0.4,0) arc (180:150:0.4);
  \draw[color=F1] (-0.35,0) arc (180:210:0.3);
  \draw[color=F1] (-0.45,0) arc (180:210:0.4);
  \draw[color=F1] (0.35,0) arc (360:330:0.35);
  \draw[color=F1] (0.45,0) arc (360:330:0.45);
  \draw[color=F1] (0.75,0.15) node[left] {\bfseries 30\degre};
  \draw (0.87,0.5) node[right] {$A$};
  \draw (-0.87,-0.5) node[left] {$B$};
  \draw (0.87,-0.5) node[right] {$C$};
  \draw(-0.87,0.5) node[left] {$D$};
  \draw(-0.1,-0.2) node {$O$};
  \draw (0,1) node[above] {$\phantom{A}$};
  \draw (0,-1) node[below] {$\phantom{D}$};
 \end{tikzpicture}
\hfill
 \begin{tikzpicture}[general,scale=1.71]
  \draw (0,0) circle (1);
  \draw (0,0)--(0.71,0.71);
  \draw (0,0)--(-0.71,0.71);
  \draw[dashed] (0,0)--(-0.71,-0.71);
  \draw[dashed] (1,0)--(-1,0);
  \draw[dashed] (0,1)--(0,-1);
  \draw (0,1) node[above] {$A$};
  \draw (-0.71,0.71) node[left] {$B$};
  \draw (-0.71,-0.71) node[left] {$C$};
  \draw(0,-1) node[below] {$D$};
  \draw(-0.1,-0.2) node {$O$};
  \draw[color=F1] (0.3,0) arc (0:45:0.3);
  \draw[color=F1] (0.4,0.2) node {\bfseries 45\degre};
  \draw[color=F1] (-0.3,0) arc (180:135:0.3);
  \draw[color=F1] (-0.4,0.2) node {\bfseries 45\degre};
 \end{tikzpicture}
 \end{exercice}
