diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/10.main/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/10.main/textbook.fr.md
index f17f41316..d520315e5 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/10.main/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/10.main/textbook.fr.md
@@ -272,7 +272,8 @@ z'=z-V_z\,t
 
 $`\mathbf{
 \left\{\begin{array}{l}
-t'=dt \\
+dt'=dt \\
+\\
 \dfrac{dx'}{dt'}=\dfrac{dx}{dt}-V_x \\
 \\
 \dfrac{dy'}{dt'}=\dfrac{dy}{dt}-V_y \\ 
@@ -293,6 +294,10 @@ v_z'=v_z-V_z \\
 
 
 
+$`\overrightarrow{v}_{M / \mathcal{R'}} = \overrightarrow{v}_{M / \mathcal{R}}-\overrightarrow{v}_{\mathcal{R'} / \mathcal{R}}`$
+
+
+
 *CLAPTMEC-FU-050* : 
 [ES] teorema de la invariancia de aceleraciones
 [FR] théorème de l'invariance des accélérations