diff --git a/docs/lib3x-polar_coordinate.md b/docs/lib3x-polar_coordinate.md
index 5cffcd87..b0e7b631 100644
--- a/docs/lib3x-polar_coordinate.md
+++ b/docs/lib3x-polar_coordinate.md
@@ -1,6 +1,6 @@
 # polar_coordinate
 
-Converts from Cartesian to Polar coordinates.
+Converts from Cartesian to Polar coordinates. It returns `[radius, theta]`.
 
 **Since:** 3.0