\begin{exercice}
Reproduire la figure ci-dessous.\\ On considère les vecteurs suivants.
\begin{colitemize}{3}
 \item $\vv{u_1}=\vv u-\vv{AB}$
 \item $\vv{u_2}=\vv v-\vv{CD}$
 \item $\vv{u_3}=\vv w-\vv{DE}$
\end{colitemize}
Construire un représentant de:
\begin{colenumerate}{2}
\item $\vv{u_1}$ d'origine $E$;
\item $\vv{u_2}$ d'origine $A$;
\item $\vv{u_3}$ d'origine $C$;
\item $\vv{u_1}$ d'extrémité $C$;
\item $\vv{u_2}$ d'extrémité $E$;
\item $\vv{u_3}$ d'extrémité $A$.
\end{colenumerate}
\begin{center}   
\begin{tikzpicture}[general, scale=0.8]
\quadrillageSeyes{(0,0)}{(8,4)}
\foreach \x/\y/\N/\pos in {0.8/4/B/below left,4/0.8/A/below left,4.8/2.4/C/below right,4/1.6/D/below right,5.6/2.4/E/above left}
{\draw (\x,\y) node {$+$}; 
\draw (\x,\y) node[\pos] {$\N$};}
\foreach \a/\b/\c/\d/\N/\pos in {1.6/2.4/0.8/4/u/left, 4/1.6/2.4/1.6/v/above,6.4/2.4/7.2/2.4/w/above}
{\draw[epais, ->, color=A1] (\a,\b)--(\c,\d);
\draw[color=A1] (0.5*\a+0.5*\c, 0.5*\b+0.5*\d) node[\pos] {{\boldmath $\vv{\N}$}};
}
\end{tikzpicture}
\end{center}
\end{exercice}
