diff --git a/doc/conf.py b/doc/conf.py
index c5f39d286dc9c..e7314347cdee9 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -201,6 +201,8 @@
         \DeclareUnicodeCharacter{2286}{\ensuremath{\subseteq}}
         \DeclareUnicodeCharacter{2713}{x}
         \DeclareUnicodeCharacter{27FA}{\ensuremath{\Longleftrightarrow}}
+        \DeclareUnicodeCharacter{221A}{\ensuremath{\sqrt{}}}
+        \DeclareUnicodeCharacter{221B}{\ensuremath{\sqrt[3]{}}}
     ''',
 }