diff --git a/basis/math/libm/libm-docs.factor b/basis/math/libm/libm-docs.factor
index 72c114487b..bf4c608d77 100644
--- a/basis/math/libm/libm-docs.factor
+++ b/basis/math/libm/libm-docs.factor
@@ -6,7 +6,7 @@ ARTICLE: "math.libm" "C standard library math functions"
 $nl
 "They can be called directly, however there is little reason to do so, since they only implement real-valued functions, and in some cases place restrictions on the domain:"
 { $example "USE: math.functions" "2 acos ." "C{ 0.0 1.316957896924817 }" }
-{ $example "USE: math.libm" "2 facos ." "0.0/0.0" }
+{ $unchecked-example "USE: math.libm" "2 facos ." "0.0/0.0" }
 "Trigonometric functions:"
 { $subsection fcos }
 { $subsection fsin }