In case you've had trouble finding the menu and assuming the 50 is the same as the 49, you can try...
PRG -> NXT -> MODES -> ANGLE
With the coordinate on the stack, pressing RECT or CYLIN will make switch accordingly.
--- On Sun, 8/3/08, Alan Golightly wrote:
From: Alan Golightly
Subject: [50g] polar to rectangular
To: 50g@yahoogroups.com
Date: Sunday, August 3, 2008, 6:56 PMHow do you exchange rect to polar and back?just change modes?