As is often the case, you get unusual answers when if you
have not conformed to the expected syntax. Certainly
cos^3(x) is not the same as (cos(x))^3, nor is
sin*(2*x) the same as sin(2*x).
Do you mean f1(x):= ( cos(sin(2*x)))^3 ?
RJF
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.
> I gave up on using it for graphics altogether.
> 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);
>
> Regs,
>
> Henry
> synthespian@uol.com.br
>
> James Amundson writes:
> > Great. Not too long ago, I wrote that none of the bugs found recently in
> > Maxima resulted in mathematically incorrect answers. Now you have to go
> > an ruin the streak.
> >
> > This bug deserves *careful* consideration.
> >
> > Thanks for the report.
> >
> > --Jim
> >
> >
> > On Fri, 2002-04-05 at 14:36, C Y wrote:
> > > I've run into a problem with the Maxima integration ability. I tried
> > > to integrate 3^log(x), and according to both hand and mathematica
> > > calculations the answer should be (x*3^log(x))/(1+log(3)). Maxima,
> > > however, gives 3^(2*log(x))/(2*log(3)). Here is a simple test to show
> > > the problem:
> > >
> > > (C1) c:3^log(x);
> > >
> > > LOG(x)
> > > (D1) 3
> > > (C2) diff(integrate(c,x),x);
> > >
> > > 2 LOG(x)
> > > 3
> > > (D2) ---------
> > > x
> > >
> > >
> > > CY
> > >
> > >
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