You can also do what a I did, I assigned a little program to the [MODE] key that toggles between rectangular or polar, to do that:
- Enter this a program in the stack
«
IF -16 FC?C
THEN -16 SF
END
»
- Press 21 [ALPHA] [ALPHA] ASN [ENTER]
Is that simple! Now every time you want to switch form rectangular to polar or vice versa, just press [LEFT-SHIFT] [ALPHA] [MODE] in other words [LEFT-SHIFT] [ALPHA] is USER