[Maxima] wrong result from function solve

Sara Pashmin sarapashm at googlemail.com
Wed Apr 18 06:30:21 CDT 2012


Hello,

I wanted to solve 3 equations, which are equal to each other:

kill(all);
z:0.01;
ratprint:false;
eq1:(2.15-x)*(y-x)-((y-x)^2/2)$
eq2:(2.2-y)*(z-y)-((z-y)^2/2)$
eq3:2.15*x-(x^2/2)$

solve([
          eq1=eq3 ,
          eq2= eq3 ,
          t=eq3],
          [x,y,t]),numer;

The answer is:
[[x=4.330183106910809,y=4.359953703703703,t=-.06534923339011925],[x=4.29664660361135,y=.006712608473711077,t=.007204789943107004],[x=-
.03018312788515193,y=4.359953703703703,t=-.06534923339011925],[x=.003353680604145053,y=.006712608473711077,t=.007204789943107004]]

I checked two terms of results but unfortunately the answers of
equations are not the same that means the equations are not equal to
each other:


x:.003353680604145053 ;
y:.006712608473711077 ;
t:.007204789943107004 ;
eq1=(2.15-x)*(y-x)-((y-x)^2/2);
eq2=(2.2-y)*(z-y)-((z-y)^2/2);
T=2.15*x-(x^2/2);

(%o11) (2.15-x)*(y-x)-(y-x)^2/2=.007204788950103592
(%o12) (0.01-y)*(2.2-y)-(0.01-y)^2/2=.007204790914096299
(%o13) 2.15*x-x^2/2=.007204789712114554

x:4.29664660361135;
y:.006712608473711077;
t:.007204789943107004;
eq1=(2.15-x)*(y-x)-((y-x)^2/2);
eq2=(2.2-y)*(z-y)-((z-y)^2/2);
T=2.15*x-(x^2/2);


(%o17) (2.15-x)*(y-x)-(y-x)^2/2=.007205399060291384
(%o18) (0.01-y)*(2.2-y)-(0.01-y)^2/2=.007204790914096299
(%o19) 2.15*x-x^2/2=.007204179601927763

What could be the problem of this solving?

Thanks and best regards

Sara


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