diff --git a/libs/math/include/psemek/math/dual.hpp b/libs/math/include/psemek/math/dual.hpp
index dc198927..6de9473e 100644
--- a/libs/math/include/psemek/math/dual.hpp
+++ b/libs/math/include/psemek/math/dual.hpp
@@ -175,6 +175,13 @@ namespace psemek::math
 		return {std::log(d.scalar), d.delta / d.scalar};
 	}
 
+	template <typename T, std::size_t N>
+	dual<T, N> sqrt(dual<T, N> const & d)
+	{
+		auto s = std::sqrt(d.scalar);
+		return {s, d.delta / (T{2} * s)};
+	}
+
 	template <typename T, std::size_t N>
 	dual<T, N> sin(dual<T, N> const & d)
 	{