On 12/2/10 2:08 PM, Nuno Miguel dos Santos Baeta wrote:
> Hello!
>
> I believe that I've found a bug in Maxima.
>
> The following command
>
> integrate(cos(x)*cos(2*x),x);
>
> gives a wrong answer with
>
> Maxima 5.22.{0,1} + GCL 2.6.8 + Windows
>
> and the right answer with
>
> Maxima 5.21.1 + GCL 2.6.8 + Windows.
>
> (Maxima 5.21.1 + GNU/Linux [Ubuntu 10.10] also gives a correct answer.
> Unfortunately I don't remember the version of GCL used to compile
> Maxima in Ubuntu 10.10.)
>
> The correct answer for this (easy to solve by hand) integral is
>
> sin(3*x)/6+sin(x)/2 [1].
>
> The wrong answer is the same in both Maxima 5.22.0 and Maxima 5.22.1.
> This wrong answer is
>
> -cos(3*x)/6-cos(x)/2 [2].
>
> It is obvious that [1] and [2] are different - just let x=0.
>
> Could someone check this integral and let me know if I'm unfortunately
> right? Is "this bug" known?
>
This has been fixed in CVS. It was reported just a short time ago.
Ray