Solving Equations for Complex Numbers

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I've set the CAS to complex mode, but the symbolic commands don't produce 
complex solutions, e.g.
'4*x^3+8*x-4' SOLVEVX
gives an empty list.

Am I doing something wrong? Does the CAS understand complex numbers?
0
Reply Borris 12/18/2005 4:40:23 PM

In article 
<1134924023.58fec87c58f249b740f40b921c33786d@roc.usenetexchange.com>,
 Borris <none@none.com> wrote:

> I've set the CAS to complex mode, but the symbolic commands don't produce 
> complex solutions, e.g.
> '4*x^3+8*x-4' SOLVEVX
> gives an empty list.
> 
> Am I doing something wrong? Does the CAS understand complex numbers?

As  you have entered it, your variable seems to be the lower case'x', 
not the upper case 'X'.

The calculator is case sensitive, and the default variable for SOLVEVX 
is an upper case 'X', not a lower case 'x'.
0
Reply Virgil 12/18/2005 7:23:05 PM


Virgil wrote:
> In article 
> <1134924023.58fec87c58f249b740f40b921c33786d@roc.usenetexchange.com>,
>  Borris <none@none.com> wrote:
> 
> 
>>I've set the CAS to complex mode, but the symbolic commands don't produce 
>>complex solutions, e.g.
>>'4*x^3+8*x-4' SOLVEVX
>>gives an empty list.
>>
>>Am I doing something wrong? Does the CAS understand complex numbers?
> 
> 
> As  you have entered it, your variable seems to be the lower case'x', 
> not the upper case 'X'.
> 
> The calculator is case sensitive, and the default variable for SOLVEVX 
> is an upper case 'X', not a lower case 'x'.

Sorry, I used an upper X
0
Reply Borris 12/18/2005 10:27:36 PM

Strange. When I do '4*X^3+8*X-4'  SOLVEVX (in complex mode, FIX 2) I
get:
{ X=(-0.23,-1.47) X=(-0.23,1.47) X=0.45 }

You might have a strange flag setting; do CASCFG and try again.

-Joe-

0
Reply Joe 12/18/2005 11:25:09 PM

In article 
<1134944856.efa44d290a5d4ace54b050d099bedb85@roc.usenetexchange.com>,
 Borris <none@none.com> wrote:

> Virgil wrote:
> > In article 
> > <1134924023.58fec87c58f249b740f40b921c33786d@roc.usenetexchange.com>,
> >  Borris <none@none.com> wrote:
> > 
> > 
> >>I've set the CAS to complex mode, but the symbolic commands don't produce 
> >>complex solutions, e.g.
> >>'4*x^3+8*x-4' SOLVEVX
> >>gives an empty list.
> >>
> >>Am I doing something wrong? Does the CAS understand complex numbers?
> > 
> > 
> > As  you have entered it, your variable seems to be the lower case'x', 
> > not the upper case 'X'.
> > 
> > The calculator is case sensitive, and the default variable for SOLVEVX 
> > is an upper case 'X', not a lower case 'x'.
> 
> Sorry, I used an upper X

The HP calculators will not find exact irrational zeros to a cubic 
polynomial, but can find approximate ones.

An alternate form for getting approximate zeros is to enter [ 4 0 8 -4] 
as the vector of coefficients and then use the PROOT command to get a 
vector of the zeros. This works regardless of flag settings.
0
Reply Virgil 12/19/2005 12:54:00 AM

 Set your calculator to approximate mode ,then using SOLVEVX  will give
the numerical answer!

0
Reply dongdong 12/19/2005 9:11:45 AM

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