Re: [Axiom-developer] "empty list" results, inverse trig substitutions, "Floats" in "solve"

[Bill Page]

On Sat, Oct 3, 2009 at 2:20 PM, William Sit <address@hidden> wrote:
>
> I can't do much with the tan problem, since we have:
>
> solve([tan(b) = a],[b])
>>>
>>> Error detected within library code:
>
> No identity element for reduce of empty list using operation
> append
>
> (You mileage may differ, since I am using a very old version of Axiom).
>
> This is clearly a bug, for the old version.
>

Both Axiom (February 2009) and OpenAxiom (current) return

(1) -> solve([tan(b) = a],[b])

   (1)  []
                                  Type: List List Equation Expression Integer

But FriCAS gives:

address@hidden:~$ fricas -nox

                 FriCAS (AXIOM fork) Computer Algebra System
                         Version: FriCAS 2009-09-17
            Timestamp: Wednesday September 30, 2009 at 22:17:16
-----------------------------------------------------------------------------
   Issue )copyright to view copyright notices.
   Issue )summary for a summary of useful system commands.
   Issue )quit to leave FriCAS and return to shell.
-----------------------------------------------------------------------------

(1) ->
(1) -> solve([tan(b) = a],[b])

   (1)  [[b= 0]]
                              Type: List(List(Equation(Expression(Integer))))
(2) ->

Regards,
Bill Page.