Re: [Maxima] Can't bring Maxima to resolve reverse of a function

hi Matrin

it is a bug maxima solve system .
Generally speaking,at more than 3 degree none linear system
we can not solve algebraically even if it is solvable.
(see Richard E.Carndall:Projects in Scientific Computation
2.1.2 2~4)
But your problem must be algebraically solvable.
Maybe at older version,we could solve this??
We must fix this bug.
till that time,by hand,use subst. example.....
 
maxima  
> 

> 
> Hi,
> 
> while I can bring Maxima to resolve a set of quotations with one set
> of variables filled in, but it doesn't work the reverse way (to find
> the numbers the first run printed).  I am sure I am trying to do
> something that Maxima doesn't support and I would be grateful for
> hints about my misunderstanding.
> 
> I'm trying to use Maxima to find the crosspoints of two hyperbolas.  To
> make sure I have valid input data, I first resolve the equotations
> with the to-be-found crosspoint (bx, by) filled in with an example.  It
> gives the the relative distances between the first and second and the
> first and third measuring point as expected:
>   delta2 = 727.7195050753926;
>   delta1 = 211.7114188973537;
> This is appended file 1, "test2.max".  It works as expected.
> 
> But when I fill in the relative distance variables anad try to resolve
> the equotation to find the coordinates of the crosspoint (bx, by),
> maxima gives no answer "[]".  This is appended file 2, "test3.max".
> 
> Definitions and assumptions used (I apologize for some bad english, I
> learned math in German).
> 
> We have a coordinate system with three known "observation points",
> which will be the base for the distance values for the hyperbolas.
> Point 1 is 0,0, point 2 is defined as on the X-Axis on op2x,0, point 3
> is anywhere at op3x,op3y.  I am looking for a point bx,by, of which I
> know "it is  more meters from op2 than op1 and  more
> meters from op3 than op1".
> 
> Variables dis1, dis2 and dis3 are the distances of the point I am
> looking for from the observation points.  They fall out when solving
> the equotations, leaving only delta1 and delta2, which I know.
> 
> Again, the first appended file "test2.max" is only to find
> known-to-be-valid delta1 and delta2 to feed into the real thing, the
> second appended file.
> 
> Maybe I need to supply input to the second solving that has two
> solutions in it, for two crosspoints, not one as I feed in? If so, how
> can I do that in Maxima?
> 
> I appreciate your comments
>        Martin
>