diff --git a/01.curriculum/01.physics-chemistry-biology/03.Niv3/01.nature light/01.electromagnetic-spectrum/01.new-course-main/textbook.en.md b/01.curriculum/01.physics-chemistry-biology/03.Niv3/01.nature light/01.electromagnetic-spectrum/01.new-course-main/textbook.en.md
index 8b09b293d..7b82537ee 100644
--- a/01.curriculum/01.physics-chemistry-biology/03.Niv3/01.nature light/01.electromagnetic-spectrum/01.new-course-main/textbook.en.md	
+++ b/01.curriculum/01.physics-chemistry-biology/03.Niv3/01.nature light/01.electromagnetic-spectrum/01.new-course-main/textbook.en.md	
@@ -1,5 +1,7 @@
 ---
 title: 'new course : main'
+published: no
 ---
 
-new course : main
\ No newline at end of file
+test :
+$`\oiint \vec{B} \cdot \vec{dS}
\ No newline at end of file