diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index 2c8a912..21ce901 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -76,4 +76,7 @@ float sineDegrees(float x);
 
 // Function to calculate the cosine of an angle in degrees
 float cosineDegrees(float x);
+
+// Function to calculate the tangent of an angle in degrees
+float tangentDegrees(float x);
 #endif
\ No newline at end of file