diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index 6c17885..28d875e 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -44,5 +44,7 @@ float cosine(float x);
 // Function to calculate the tangent of an angle in radians
 float tangent(float x);
 
+// Function to calculate the arc sine of a value and return the result in radians
+float arcSine(float x);
 
 #endif
\ No newline at end of file