On Sat, 2002-04-13 at 13:44, synthespian wrote:
> Hi James-
>
> I disagree that Maxima is trustworthy. There are little bugs here
> and there. More than I have time to report or annotate.
Please send in any mathematical bugs you find.
> I gave up on using it for graphics altogether.
The graphics are in very bad shape. We know that. We also have plans to
improve graphics in Maxima, but it may take a while.
> I hope for better days.
>
> Let me give you another bug, involving differentiation:
>
> (C1) f1(x):= (cos^3*(sin*(2*x)));
> (C2) diff(f1(x),x);
> This evaluates to the bizarre answer:
>
> 2 x cos^3 DEL(sin) + 6 x cos^2 sin DEL(COS) + 2 cos^3 sin DEL(x)
>
> The correct answer, by hand and confirme with Maple, is:
>
> 6 cos^2(sin(2x))*sin(sin(2x))*cos(2x);
As Richard said, the bug is in your input form. If you want the cube of
the cosine of the sine of 2 times x, you should use the syntax he gave.
Maxima will reward you with the correct derivative. There appears to be
a sign error in the "Maple" answer, but I'll assume that's just a
transcription error.
--Jim