diff --git a/question_21.m b/question_21.m
index 757b2982857f1cd470cfd85f0e34677e2e54518e..08cb3251953a046aa2f8804afe0628098d2bbf03 100644
--- a/question_21.m
+++ b/question_21.m
@@ -31,7 +31,7 @@ xlabel('f (Hz)')
 ylabel('10log(|X_1|)')
 title('spectre du signal en dent de scie');
 
-%question 2.2------------------------------------------
+% Question 2.2------------------------------------------
 
 % Filtrage : y(k) = 1/2 (x(k) + x(k-1))
 b=[1/2,1/2];