[Maxima-bugs] [ maxima-Bugs-2969546 ] Does not solve simple equation

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Bugs item #2969546, was opened at 2010-03-12 19:04
Message generated for change (Comment added) made by stefan-d
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Category: Lisp Core - Solving equations
Group: None
Status: Closed
Resolution: None
Priority: 5
Private: No
Submitted By: jamlatino (jamlatino)
Assigned to: Nobody/Anonymous (nobody)
Summary: Does not solve simple equation

Initial Comment:
Maxima is not able to solve this simple equation
400-(800*(6-x))/sqrt((6-x)^2+4)=0


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Comment By: Stefan Dermitzakis (stefan-d)
Date: 2010-03-16 14:52

Message:
I have the same problem and sorry, i think you all have not understand the
problem.
The bug is that maxima cannot recognize the unknow  x  inside the
sqrt(.....) in 
the equation.
Note: the old Mcsyma have the same problem.
          Possibly many other bugs in maxima have the same cause.

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Comment By: Dieter Kaiser (crategus)
Date: 2010-03-14 14:54

Message:
The example of this bug report has been added to the open feature request 
ID: 2617416 "to_poly_solve in core, was: Maxima can't solve equation".
Closing this bug report.
Dieter Kaiser


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Comment By: Dieter Kaiser (crategus)
Date: 2010-03-12 20:19

Message:
Maxima is able to solve this equation with the Maxima function
to_poly_solve. The package to_poly_solver has to be loaded first:

(%i3) load(to_poly_solver);
(%o3) "/usr/local/share/maxima/5.20post/share/contrib/to_poly_solver.mac"

(%i4) eqn:400-(800*(6-x))/sqrt((6-x)^2+4)=0$

(%i5) to_poly_solve(eqn,x);
(%o5) %union([x = (2*3^(3/2)-2)/sqrt(3)])

I suggest to add a comment about to_poly_solve to the documentation of
solve and close this bug report. It might be arguable to extend the Maxima
function solve to handle this equation too. But this would be a feature
request.

Dieter Kaiser

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