diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index e26c1a5..fde7c2c 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -61,4 +61,9 @@ float radiansToDegrees(float x);
 
 // Function to calculate the base 10 logarithm of a number and add 1
 float logarithmPlusOne(float x);
+
+// Function to calculate the natural logarithm (base e) of a number and add 1
+float naturalLogarithmPlusOne(float x);
+
+
 #endif
\ No newline at end of file