Big problem in solving radicals.
- To: mathgroup at smc.vnet.net
- Subject: [mg41744] Big problem in solving radicals.
- From: davide at astromeccanica.it (Davide Del Vento)
- Date: Tue, 3 Jun 2003 07:13:28 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Consider the following equation
1/2
x + a = 0
If you try to solve it with "Solve" you get
2
x = a
Of course, you know, this is not a general solution, e.g. if a>0 there
isn't any (real) solution, and the complex solution is NOT the one
printed by Mathematica.
In the case of this example the problem is obvious and one can track
it by hand, but what's about bigger equations with many solutions?
Mathematica claims that "Solve" makes special assumptions about the
parameters in the equation, so I was ready to such behaviour. I tested "Reduce"
that should solve equation, giving explicitely the range of the
parameters where the solutions are defined. Unfortunately it doesn't
work right too.
;Davide Del Vento
CNR Istituto Fisica Spazio Interplanetario
via del Fosso del Cavaliere, 100 / IT-00133 / Rome
Phone: +390649934357
Fax: +390649934383
Mobile: +393288329015
E-Mail: davide @ astromeccanica.it
E-Mail: del vento @ ifsi . rm . cnr . it