Re: Matrix Form of Quadratic Equations
- To: mathgroup at smc.vnet.net
- Subject: [mg114254] Re: Matrix Form of Quadratic Equations
- From: Fred Simons <f.h.simons at tue.nl>
- Date: Mon, 29 Nov 2010 06:06:11 -0500 (EST)
Op 28-11-2010 12:54, Simon schreef:
> On Nov 26, 6:32 pm, Ari<ari... at finly.net> wrote:
>> Hello,
>>
>> Could anyone guide me how to build a mathematica module to form a Matrix
> form from a quadratic equations?
>> For example, x^2 + y^2 - 2 x y will output
>> {{1, -1}, {-1, 1}} ?
>>
>> Thanks
> Hi there,
>
> I was sure that you would be inundated with answers...
(....)
Yes, that was my feeling too. The good old SolveAlways (unchanged since
version 1) seems to be forgotten:
In[198]:= SolveAlways[{x,y}. {{a,b},{b,c}}. {x,y}== x^2 + y^2 - 2 x y,
{x,y}]
Out[198]= {{a->1,b->-1,c->1}}
Fred Simons
Eindhoven University of Technology