diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index a46892d..2c8a912 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -73,4 +73,7 @@ float cubeRootPlusOne(float x);
 
 // Function to calculate the sine of an angle in degrees
 float sineDegrees(float x);
+
+// Function to calculate the cosine of an angle in degrees
+float cosineDegrees(float x);
 #endif
\ No newline at end of file