Re: Iteration on 33s or 35s? Message #2 Posted by Karl Schneider on 30 Oct 2007, 12:46 a.m., in response to message #1 by Howard Boardman
Howard 
It sounds as though you are melding two different things:
 Polynomials having an order n and one variable for n possible roots (solutions)
 Multivariable equations
However, I'm fairly sure that I know the gist of your question: You're wondering why you always get the same result when solving for the only unspecified variable, which appears only once in the equation.
The answer is that the HP33s and HP35s will provide a "direct solution" determined by internal algebraic methods, in cases where it deems possible. They will ignore your two initial guesses to provide this direct solution. This flawed logic was borrowed from the solver in the HP19B/II and HP27S.
The workaround is to add a mathematically inert term such as "+0*X" to the equation in order to trick the calculator into concluding that the equation is algebraically intractable. Then, it will use numerical iteration with your initial guesses.
An archived thread and an article:
http://www.hpmuseum.org/cgisys/cgiwrap/hpmuseum/archv014.cgi?read=62608#62608
HP SOLVEINTEG on all RPNbased models
As for the last part of your query: There may be an infinite number of solutions for a single multivariable equation. Solution for multiinput, multioutput systems of equations is not supported by the HP33s or HP35s. An HP50g can be used for that purpose.
 KS
Edited: 30 Oct 2007, 1:27 a.m. after one or more responses were posted
