diff --git a/424-Systeme_Non_Lineaires/Cours/chap4.tex b/424-Systeme_Non_Lineaires/Cours/chap4.tex
index 247a10e..406f9aa 100644
--- a/424-Systeme_Non_Lineaires/Cours/chap4.tex
+++ b/424-Systeme_Non_Lineaires/Cours/chap4.tex
@@ -19,7 +19,15 @@ On prend $x=X\sin \omega t$. Dans le cas linéaire, seule la valeur de $\omega$
 
 \begin{figure}[h!]
 \centering
-\includegraphics[scale=0.4]{2/424-1.png}
+\begin{tikzpicture}
+  \draw[-latex] (-4,0) -- (4,0)node[above]{$Re$};
+  \draw[-latex] (0,-4) -- (0,4)node[left]{$Im$};
+  \draw (0,0) to[out=110,in=0]  (-2,1)   to[out=180,in=80] (-4,-3) node[below]{$X_1$};
+  \draw (0,0) to[out=130,in=0] (-1,0.7)  to[out=180,in=80] (-3,-3)node[below]{$X_2$};
+  \draw (0,0) to[out=150,in=0] (-0.5,0.3) to[out=180,in=80](-2,-3) node[below]{$X_3$};
+  \node[above] at (-2,1) {$T_{BO}$};
+\end{tikzpicture}
+ \caption{Modification du lieu en fonction de l'amplitude}
 \end{figure}
 
 Puisque $H(p)$ rejette les harmoniques d'ordre supérieur à 1, on peut donc décomposer \[y(t)=P \sin \omega t + Q \cos \omega t\]
@@ -294,24 +302,36 @@ i.e. en notant $\left.\derivp[]{X}\right|_{\zero}=\left.\derivp[]{X}\right|_0$
   \centering
   \begin{tikzpicture}
     \begin{axis}
-      [axis lines= middle,
-      ticks=none, domain=0:10,
-      xmin=0,xmax=10,ymin=-2,ymax=2]
-      \addplot[black,smooth]{cos(2*deg(x))};
-      \addplot[black,smooth]{cos(2*deg(x))*(exp(x/10))};
-
+      [axis lines= middle,scale=0.8,
+      ticks=none, domain=0:10,samples=100,
+      xmin=0,xmax=10,ymin=-2,ymax=2,clip=false]
+      \addplot[black,smooth,dashed]{cos(2*deg(x))};
+      \addplot[black,smooth]{cos(2*deg(x))*(1+0.3*exp(x/8))};
+      \addplot[black,smooth]{cos(2*deg(x))*(1+0.3*exp(-x/5))};
+      \draw[-latex] (axis cs: -0.1,1) -- (axis cs: -0.1,1.3) node[midway,left]{$\delta x >0 $};
+      \draw (axis cs:10,1.5) node[right]{$m>0$};
+      \draw (axis cs:10,0.5) node[right]{$m<0$};
     \end{axis}
+  \end{tikzpicture}\qquad%
+  \begin{tikzpicture}
+  \begin{axis}
+      [axis lines= middle,scale=0.8,
+      ticks=none, domain=0:10,samples=100,
+      xmin=0,xmax=10,ymin=-2,ymax=2,clip=false]
+      \addplot[black,smooth,dashed]{cos(2*deg(x))};
+      \addplot[black,smooth]{cos(2*deg(x))*(1-0.3*exp(x/8))};
+      \addplot[black,smooth]{cos(2*deg(x))*(1-0.3*exp(-x/5))};
+      \draw[-latex] (axis cs: -0.1,1) -- (axis cs: -0.1,0.7) node[midway,left]{$\delta x< 0$};
+      \draw (axis cs:10,0) node[right]{$m>0$};
+      \draw (axis cs:10,0.5) node[right]{$m<0$};
+    \end{axis}
+  
   \end{tikzpicture}
-\includegraphics[scale=0.4]{2/424-61.png}
 \end{figure}
 $m > 0$ et $\delta X > 0$ : CL est stable
 
 $m < 0$ et $\delta X > 0$ : CL est instable
 
-\begin{figure}[h!]
-\centering
-\includegraphics[scale=0.4]{2/424-62.png}
-\end{figure}
 $\delta X < 0$ et $m < 0$ : CL est stable
 
 $\delta X < 0$ et $m > 0$ : CL est instable