diff --git a/chapters/functions.tex b/chapters/functions.tex
index 3d4fbd2c5..d6023262a 100644
--- a/chapters/functions.tex
+++ b/chapters/functions.tex
@@ -1186,7 +1186,7 @@ \subsection{Using the Derivative Annotation}\label{using-the-derivative-annotati
 \begin{nonnormative}
 A straightforward way of explaining a valid derivative is given by this model.
 The function value, \lstinline!x1!, should up to numerical precision match the integral of the derivative, \lstinline!x2!.
-Note that in practive tools may over-optimize this.
+Note that in practice tools may over-optimize this.
 \begin{lstlisting}[language=modelica]
   function f
     input Real x;