Well, as many Maxima commands as possible should respect a common sign
convention for
sqrt(). Some may not work that way for a legitimate reason.
-----Original Message-----
From: Richard Hennessy
Sent: Saturday, November 13, 2010 7:46 PM
To: Richard Fateman ; Maxima - list
Subject: Re: [Maxima] caps complex tests
If radcan() can change the sign of the answer with no notice that would
confuse a lot of people, and it is not a simpler answer. The original
expressions (both of them) are positive when you plot from zero to 1 or 10
or 100, the radcan'ed expression is negative when you plot from zero to 1,
or 10 or 100. Most people, like me, who think that radcan() is another kind
of simplify command will be confused by this. They may have a hard time
figuring out why the answer has a different sign. You say it is okay to
change the sign when you radcan(). At the very least there should be a
warning about this in the help. Something that says that radcan may do more
than simplify because it might change the sign if it wants to. Some notice
of when this sign change may occur should be in the help too.
You can argue that there is no sign change problem because the answer is
correct if you consider that 1/sqrt(x) could mean the negative root of x,
but other Maxima functions like integrate, plot and draw do not choose that
answer. All maxima commands should respect a common sign convention for
sqrt().
Rich