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 a608276cb..cb88475a7 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
@@ -202,5 +202,13 @@ PartÃcula :
[CME][FR] $`\overrightarrow{L}=\overrightarrow{r}\wedge\overrightarrow{p}`$
-[ES]
+[ES] producto cruz, en coordenadas cartesianas :
+
+
+
+$`\overrightarrow{L}=\begin{vmatrix}
+\hat{i}&\hat{j}&\hat{k}\\
+x & y & z\\
+p_x & p_y & p_z\end{vmatrix}`$
+