[Maxima] The factor function is a little bit silly.
macrakis at alum.mit.edu
Tue Apr 8 07:20:51 CDT 2008
On Tue, Apr 8, 2008 at 12:27 AM, J.C. Pizarro <jcpiza at gmail.com> wrote:
> So, if Maxima knows about "sqrt" then it should factor the above formula
> "symbolically" but it didn't wrong it because it believed that was
> doing "numerically" sqrt(a) for all real points of a instead of "symbolically",
> i supposed it.
No. It is because sqrt(x)==x^(1/2). So sqrt(x)^2 = x, but sqrt2(x)^2
= sqrt2(x)^2 just as pizarro(x)^2 = pizarro(x)^2.
> Then it's a bug of Maxima in the symbolic computation when the name of
> its symbol matches with the name of the (pre)defined function sqrt.
No. It is because sqrt == ^(1/2) has algebraic properties that sqrt2
does not have.
> In theory, it's not true (e.g. if the computation is realized in lazy mode or
> intelligent mode), but in the practice, the longer time is due to its weaker
> implementation that doesn't support the solving of stronger formulas.
Maxima might be able to use lazy techniques effectively in some cases.
Perhaps you can work on that.
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