Update textbook.fr.md

00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/10.main/textbook.fr.md

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