From 58cf889a1ccaa448b5105640702a5ba5be0bf291 Mon Sep 17 00:00:00 2001
From: Claude Meny <claude.meny@irap.omp.eu>
Date: Tue, 1 Sep 2020 12:53:54 +0200
Subject: [PATCH] Update textbook.fr.md

---
 .../textbook.fr.md                                       | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
index ea814624f..5f238322f 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
@@ -670,9 +670,12 @@ en coordenadas cilíndricas son :<br>
 coordonnées cylindriques sont :<br>
 [EN] According to the chosen direction, the **scalar surface elements $`dA`$** in 
 cylindrical coordinates are :<br>
-<br>$`dA_{\rho\varphi}=dl_{\rho}\;dl\varphi=d\rho\cdot\rho\;d\varphi\quad`$, 
-$`\quad dA_{\rho z}=dl_{\rho}\;dlz=d\rho\;dz\quad`$, $`\quad dA_{\varphi z}
-=dl_{\varphi}\;dlz=\rho\,d\varphi\;dz`$<br>
+<br>$`dA_{\rho\varphi}=dl_{\rho}\;dl\varphi=d\rho\cdot\rho\;d\varphi\quad`$,
+en una superficie tal que $`z=cst`$.<br>
+$`dA_{\rho z}=dl_{\rho}\;dlz=d\rho\;dz\quad`$,
+en una superficie tal que $`\varphi=cst`$.<br>
+$`dA_{\varphi z}=dl_{\varphi}\;dlz=\rho\,d\varphi\;dz`$
+en una superficie tal que $`\rho=cst`$.