[kde-edu]: [KDE-EDU] KMathTool, Finding roots of Cubic polynomial

[Roberto Moriyon]

Hi,

in http://www.chez.com/sereinarts/ax3bx2cxd.html there is an algorithm 
written in C that is suposed to solve the general cubic equation.

Regards,

Roberto

Trenton Carr wrote:

> Hello all
>
> I'm trying to implement a class that takes the (math)function of a  
> hyperbola and parabola, solves them simultaneously by finding the 
> roots of  a cubic polynomial. This gives the intercepts between the two.
>
> ie:    hyperbola y = k/x
>     parabola  y = ax^2+bx+c
>
> solve simultaneously:    ax^3+bx^2+cx-k
>
> this can be solved by factorizing the cubic by factor theorem, like so,
>
>         (x+?)(ax^2+bx+c)    where ? = Int.     ? can be found by 
> inspection and  algebraic long division.
>
> Does anyone know how to do this programmagically.
> I've googled myself silly and to be honest, I don't even know where 
> to  start asking for help with this.
>
> I need this to calculate the intecepts between a hyperbola and a 
> parabola  which I'm plotting for KMathTool.
>
> Any help from you TechnoMages would be appreciated.
>
> Kind Regards
>
> Trenton
>
>

-- 

Roberto Moriyon
Department of Computer Engineering
Unversidad Autonoma de Madrid
C/ Francisco Tomas y Valiente, 11
28049 Madrid (Spain)

Phone: +34-91-497-2282
Fax: +34-91-497-2235