On 10/07/2008, at 2:14 PM, François Bissey wrote:
>
> On Thu, 10 Jul 2008, Robert Dodier wrote:
>> William Stein wrote:
>>> If you answer could you summarize what Maple/Mathematica do
>>> (if you care), and if so why you think whatever you propose is
>>> better than them.
>>
>> Not sure if I am the "you" in question here, but fwiw I don't know
>> what Maple or Mathematica do when there are multiple solutions.
>>
> I think he was general. Anyway from memory:
> Mathematica returns a list
> {{solution-1, condition-1},........,{solution-n, condition-n}}
> unless you passed an assumption to the command.
> Command[expression,Assumptions->{some list}]
> Actually Mathematica is a bit inconsistent there. The keyword
> Assumptions can only be used in certain command (Integral
> comes to mind but I am not sure that's the only one), while
> some other like the Simplify familly don't (I am pretty sure):
> Simplify[expr,{some assumptions}]
Multiple solutions are different to assumptions in Mathematica.
Solve[x^2 == 1, x] returns a two unconditional solutions. (x -> 1, x-
> -1 are both solutions).
Integrate[x^a, {x, 1, Infinity}] returns an answer that incorporates
assumptions:
If[Re[a] < -1, -(1/(1 + a)), Integrate[x^a, {x, 1, ∞}, Assumptions ->
Re[a] >= -1]]
If you want me to unpack that or have a more instructive example, just
ask.
D
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to sage-devel@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at http://groups.google.com/group/sage-devel
URLs: http://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---
