diff -r 76e9c3e876d4 Doc/library/math.rst
--- a/Doc/library/math.rst	Sun May 29 20:46:27 2011 +0200
+++ b/Doc/library/math.rst	Sun Jun 05 12:31:19 2011 +0900
@@ -33,8 +33,8 @@
 
 .. function:: copysign(x, y)
 
-   Return *x* with the sign of *y*.  On a platform that supports
-   signed zeros, ``copysign(1.0, -0.0)`` returns *-1.0*.
+   Return a float with the magnitude of *x* but the sign of *y*.  On a platform
+   that supports signed zeros, ``copysign(1.0, -0.0)`` returns *-1.0*.
 
 
 .. function:: fabs(x)