# [Maxima] Working with Inequalities

Tue Mar 27 09:57:27 CDT 2012

```Thanks, Volker. It was helpful.

Now my only problem is to solve of the inqualities: [((x)^2-8)<0 , (x)<0].

For the inaualities: [((x)^2-9)<0 , (x)<0] :
fourier_elim( [((x)^2-9)<0 , (x)<0], [x]);
[-3<x,x<0]

But the solve of the first inaualities is:

[ x<0, -(x^2-8)>0]

I tried to use the functions of equalities like "allroots (eqn)" and
"bfallroots (eqn)" but they were not helpful.

Regards

Sara Pashmin

Am 27. März 2012 16:24 schrieb Volker van Nek <volkervannek at googlemail.com>:
> (%i1) display(foo)\$
>                                    foo = foo
>
> (%i2) disp(foo)\$
>                                       foo
>
> Maybe disp is what you want.
>
> Volker van Nek
>
> 2012/3/27 Sara Pashmin <sarapashm at googlemail.com>
>>
>> Hello,
>>
>> I try to solve inequalities of a list with Maxima.
>>
>> A simple example is:
>>
>> y : [1,4,8]\$
>> for i:1 step 1 thru length(y) do
>> ( tt[i]: %solve( [(x[i]^2-y[i])<0, (x[i])<0], [x[i]]),
>> display (tt[i])
>> );
>>
>>
>> (%o144) [1,4,8]
>> tt[1]=%union([-1<x[1],x[1]<0])
>> tt[2]=%union([-2<x[2],x[2]<0])
>> tt[3]=%union([x[3]<0,-(x[3]^2-8)>0])
>> (%o145)
>>
>> I would like to know :
>>
>> 1) how to get a result of tt[3] like that:
>>
>> %union( [x[3]<0 , x[3]>-2.828])
>>
>> and:
>> 2) how to display the results of "x" without using "display (tt[i])".
>> For example when I use the single variable (without list and "for") like
>> this:
>> y : 8\$
>> %solve( [(x^2-y)<0, (x)<0], [x]);
>> I get the following result of x:
>> (%o157) %union([x<0,-(x^2-8)>0])
>>
>> I will be thankfur for help,
>>
>> Best Regards
>>
>> Sarah
>> _______________________________________________
>> Maxima mailing list
>> Maxima at math.utexas.edu
>> http://www.math.utexas.edu/mailman/listinfo/maxima
>
>
```