On Tue, Apr 22, 2008 at 1:20 PM, Robert Marik <marik at mendelu.cz> wrote:
> solve([log(y^2+x^2)+2*x^2/(y^2+x^2)=0,2*x*y/(y^2+x^2)],[x,y])
> [[x=0,y=0]]
>
> I think that the answer is wrong, since the equations are undefined at
> [0,0].
>
Yes, that answer is wrong; Maxima, alas, in general doesn't do a good job
with "caveats".
And, worse, solve missed the perfectly good solutions [x=1/%e,y=0] and
[x=0,y=1]. That is a more severe problem. (In some narrow technical sense
not a bug, since for multiple equations solve uses algsys and so assumes
they're algebraic, but from the user's point of view, it really is a bug.)
-s