\begin{methode}[Lire les coordonnées d'un vecteur \MethodeRefExercice*{2G3_E_lire_coord}]
\exercice[0.55]\label{2G3_M_lire_coord}
  Lire les coordonnées du vecteur $\vv u$ sur la figure ci-dessous. 
  \vspace{-0.5em}
\begin{center}
\begin{tikzpicture}[general, yscale=0.6]
\foreach \a/\b/\c/\d in {0/0/5/0, 0/0.87/5/0.87, 0/2.61/5/2.61, 0/3.48/5/3.48, 0/1.74/1/3.48, 1/0/3/3.48, 2/0/4/3.48, 3/0/5/3.48, 4/0/5/1.74} {\draw[quadrillage] (\a,\b)--(\c, \d);}
\draw[axe] (0,0)--(2,3.48); 
\draw[axe] (0,1.74)--(5,1.74);
\coordinate (I) at (2,1.74); 
\coordinate (J) at (1.5,2.61); 
\draw (I) node[rotate=-25] {{\boldmath $/$}} node[below]{$I$};
\draw (J) node {{\boldmath $-$}} node[left]{$J$};
\draw[epais, ->, line cap=butt, color=F1] (0.5,2.61)--(3,0);
\draw (1.25,1.305) node[below] {{\boldmath $\vv{u}$}};
\end{tikzpicture}
\end{center}
 \correction
\begin{tikzpicture}[general, yscale=0.6]
\foreach \a/\b/\c/\d in {0/0/5/0, 0/0.87/5/0.87, 0/2.61/5/2.61, 0/3.48/5/3.48, 0/1.74/1/3.48, 1/0/3/3.48, 2/0/4/3.48, 3/0/5/3.48, 4/0/5/1.74} {\draw[quadrillage] (\a,\b)--(\c, \d);}
\draw[axe] (0,0)--(2,3.48); 
\draw[axe] (0,1.74)--(5,1.74);
\coordinate (I) at (2,1.74); 
\coordinate (J) at (1.5,2.61); 
\draw (I) node[rotate=-25] {{\boldmath $/$}} node[below]{$I$};
\draw (J) node {{\boldmath $-$}} node[above left]{$J$};
\draw[epais, ->, line cap=butt, color=F1] (0.5,2.61)--(3,0);
\draw (1.25,1.305) node[below, color=F1] {{\boldmath $\vv{u}$}};
\draw[epais, ->, line cap=butt, color=A1] (0.5,2.61)--(4.5,2.61);
\draw (2.5,2.61) node[above, color=A1] {{\boldmath $+4$}};
\draw[epais, ->, line cap=butt, color=A1] (4.5,2.61)--(3,0);
\draw (3.75,1.305) node[right, color=A1] {{\boldmath $-3$}};
\end{tikzpicture}

Les coordonnées de $\vv u$ sont $\left(\begin{array}{c}
4 \\ -3
\end{array}\right)
$.
\end{methode}
