diff --git a/doc/tutorial.xml b/doc/tutorial.xml
index a5501a1..fadc7e2 100644
--- a/doc/tutorial.xml
+++ b/doc/tutorial.xml
@@ -42,7 +42,7 @@
     </para>
     
     <screen>
-      cc tut1.c -lcomedi -o tut1
+      cc tut1.c -lcomedi -lm -o tut1
     </screen>
     <para>
       The