diff --git a/xml/chapter2/section5/subsection1.xml b/xml/chapter2/section5/subsection1.xml
index 98989015d..e581f35eb 100644
--- a/xml/chapter2/section5/subsection1.xml
+++ b/xml/chapter2/section5/subsection1.xml
@@ -1000,7 +1000,7 @@ function install_complex_package() {
 // provided by GitHub user clean99
 
 function is_equal_to_zero(x) {
-    return apply_generic("is_equal", list(x));
+    return apply_generic("is_equal_to_zero", list(x));
 }
 
 function install_javascript_number_package() {