solutions of simple polynomial equations not exact



The commercial Macsyma does this exactly.  Perhaps you realize that
1.2599... is the cube root of 2, and 0.7937.. is 1/1.2599..

The answer does require the solution of a cubic, and someone apparently made
the decision that you didn't want to see that exactly.

You can get exact answers to
x^2=r*y     
y^2=x/s

and then substitute 2 for r and s.


RJF


> -----Original Message-----
> From: maxima-bounces at math.utexas.edu [mailto:maxima-
> bounces at math.utexas.edu] On Behalf Of Henning Siebel
> Sent: Tuesday, November 28, 2006 3:06 AM
> To: maxima at math.utexas.edu
> Subject: solutions of simple polynomial equations not exact
> 
> Hello,
> 
> im new to maxima and can't find out how to 'force' maxima finding/printing
> the
> exact solutions of:
> 
> a: x^2=2*y$;
> b: y^2=x/2$;
> 
> This is -among others- what I tried:
> 
> solve([a,b],[x,y]), realonly:true;
> [[x=1.259921095381759,y=0.79370052770449],[x=0,y=0]]
> 
> As the equations are simple, I (still) expect that maxima is capable of
> calculating exact solutions... - but how?
> 
> Any answers or hints?
> 
> Henning
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