diff --git a/math1052/lecture-04.html b/math1052/lecture-04.html
index f51f51b44..b74a1054b 100644
--- a/math1052/lecture-04.html
+++ b/math1052/lecture-04.html
@@ -570,7 +570,7 @@ <h4>1 Ordinary Differential Equations</h4>
 t = (0:0.05:0.6); 
 y(1) = 0;
 for i = 1:12
-    y(i+1) = y(i) + 2 * t(i) * 0.05;
+  y(i+1) = y(i) + 2 * t(i) * 0.05;
 end 
 y(13)
 plot(t, y,'-')
@@ -656,7 +656,7 @@ <h4>1 Ordinary Differential Equations</h4>
 									x = (0:0.01:2);
 									y(1) = 1;
 									for i = 1:200
-									    y(i+1) = y(i) + sin(x(i) * y(i)) * 0.01;
+									  y(i+1) = y(i) + sin(x(i) * y(i)) * 0.01;
 									end 
 									y(201)
 									plot (x,y,'-')