Re: Explicit solution to Root[]
- To: mathgroup at smc.vnet.net
- Subject: [mg58425] Re: [mg58407] Explicit solution to Root[]
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sat, 2 Jul 2005 04:06:23 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
$Version
5.1 for Mac OS X (January 27, 2005)
N[Root[-2*#1^3 + 2*#1^4 - #1*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 -
108*#1^4 + 216*#1^5 & , 1] -
6*#1^2*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 &
, 1] +
6*#1^3*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 &
, 1] -
5*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 & , 1]
^2 -
6*#1*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 & ,
1]^2 +
6*#1^2*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 &
, 1]^2 -
2*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 & , 1]
^3 +
2*#1*Root[-4 - 3*#1 + 66*#1^2 + 80*#1^3 - 108*#1^4 + 216*#1^5 & ,
1]^3 & , 2]]
1.11221
Bob Hanlon
>
> From: "Mukhtar Bekkali" <mbekkali at gmail.com>
To: mathgroup at smc.vnet.net
> Date: 2005/07/01 Fri AM 02:01:59 EDT
> Subject: [mg58425] [mg58407] Explicit solution to Root[]
>
> Here is the code:
>
> \!\(\(Root[\(-2\)\ #1\^3 + 2\ #1\^4 - #1\ Root[\(-4\) - 3\ #1 + 66\
> #1\^2 +
> 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5 &, 1] - 6\ #1\^2\
> Root[\(-4\) - \
> 3\ #1 + 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5 &,
> 1] + 6\ #1\^3\ Root[\(-4\) - 3\ #1 +
> 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5 &, 1] - 5\ \
> Root[\(-4\) - 3\ #1 + 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5
> &, \
> 1]\^2 - 6\ #1\ Root[\(-4\) - 3\ #1 + 66\ #1\^2 + 80\ #1\^3 - 108\ #1
\^4
> +
> 216\ #1\^5 &, 1]\^2 + 6\ #1\^2\ Root[\(-4\) - 3\ #1 +
> 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5 &,
> 1]\^2 - 2\ Root[\(-4\) -
> 3\ #1 + 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4 + 216\ #1\^5
> &, 1]\
> \^3 + 2\ #1\ Root[\(-4\) - 3\ #1 + 66\ #1\^2 + 80\ #1\^3 - 108\ #1\^4
+
> 216\ \
> #1\^5 &, 1]\^3 &, 2];\)\)
>
> I would guess it is a number. I applied RootReduce, ToRadicals, N or
> combinations of thereof, however, nothing seem to convert the above
> expression into an explicit number. What command or sequence of
> commands would do the job? Please advise. Thanks,
>
> Mukhtar Bekkali
>
>