Re: [Axiom-math] relate root representations

[Bill Page]

On Sat, Nov 15, 2008 at 5:23 PM, Alejandro Jakubi wrote:
>
> As a concrete example, in a follow-up of the example that I have posted
> a few weeks ago, consider the lists produced by:
>
> allRootsOf(p^3 - p + 1/10)$RECLOS(FRAC INT)
>
> [%F8,%F9,%F10]
>
> solve((p^3 - p + 1/10=0)::EQ EXPR INT,p)
>
>
>              +-----------+             +-----------+
>              |      2                  |      2
>             \|- 3%p0  + 4  - %p0    - \|- 3%p0  + 4  - %p0
>  [p= %p0,p= --------------------,p= ----------------------]
>                       2                        2
>                                 Type: List Equation Expression Integer
>
> radicalSolve(p^3 - p + 1/10=0,p)
>
> So, I mean eg a command that takes %F8 as input and gives as output the
> correspondig equation (or rhs) in the second or third list.
>
> Is there such command?
>

No there is no such command since RECLOS does not actually solve for
the roots exactly. It only finds the intervals within which each
unique real root lies. But in a previous email I suggested a simple
routine that did a lookup of the exact root based on computing it's
floating point value. Didn't you like that approach?

Regards,
Bill Page.