Note, that, in 5.11.0 'topoly' is not in the manuals.
(%i1) build_info();
Maxima version: 5.11.0
Maxima build date: 4:28 1/25/2007
host type: i686-pc-linux-gnu
lisp-implementation-type: GNU Common Lisp (GCL)
lisp-implementation-version: GCL 2.6.7
(%o1)
(%i2) ? topoly;
(%o2) false
On Mon, 29 Jan 2007, Barton Willis wrote:
> maxima-bounces at math.utexas.edu wrote on 01/29/2007 05:07:22 AM:
>
>> Trying to solve a system of equations with radicals, i get an error
> message:
>>
>> (%i1) solve([x+3*y=5,sqrt(x+y)-1=y]);
>>
>> `algsys' cannot solve - system too complicated.
>> -- an error. Quitting. To debug this try debugmode(true);
>
> (%i1) load(topoly)$
> (%i2) e : [x+3*y=5,sqrt(x+y)-1=y]$
> (%i3) ep : map('topoly,e);
> (%o3) [3*y+x-5=0,y^2+y-x+1=0]
> (%i4) sol : algsys(ep,[x,y]);
> (%o4) [[x=11-6*sqrt(2),y=2*sqrt(2)-2],[x=6*sqrt(2)+11,y=-2*sqrt(2)-2]]
> (%i5) for si in sol do print(float(subst(si,e)));
> [5.0=5.0,0.82842712474619=0.82842712474619]
> [5.000000000000002=5.0,2.82842712474619=-4.82842712474619]
>
> The function topoly potentially makes the solution set larger. It seems
> that sol[1] is a solution, but sol[2] isn't. The float method for
> checking solutions is crude, but I think that a symbolic check
> would involve denesting square roots. Maybe you can get
> Maxima to check the solutions symbolically.
>
> Barton
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