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WP 34S Solver
05-28-2015, 04:19 AM (This post was last modified: 05-28-2015 11:36 AM by AnalogJoe.)
Post: #20
RE: WP 34S Solver
Well as far as I know you only have to provide an initial guess, as opposed to the intervals of solution. The WP 34s developers may shed some light into this issue, but im pretty sure the Solver uses somekind of open method such as Newton-Rhapson, or similar..

I have mixed feelings about these type of HP numeric solvers, on one hand they are extremely painful when it comes to solving polynomials because they will only find one particular root, and you have to constantly change your initial guess in order to find the different roots, at this point it is useful to remember Descartes rule of signs to get a better idea of what you should be looking for.

However if you are looking for a complex root, then you are out of luck, these solvers wont find it, I had to program a complex solver on my 35s to do this, and will probably have to do the same for the WP 34s. So finding polynomial roots with these solvers is a painstaking process, something that an off the shelf Casio will happily do up to 3rd order polynomials including complex roots, the WP34s only has a dedicated quadratic solver with complex root finding capability.

One could argue that not every day (at least not in my case) you need to solve a polynomial of a degree higher than 3, so lets say for a moment that 3rd degree is the highest degree poly for common applications, if the polynomial has 3 real roots then the HP solver will find them, but many times not all the roots wil be real, in that case, you dont need the HP solver to find the complex roots (in case they exist), instead you only need to find a real root, and since a 3rd degree poly with real coefficients will always have at least one real root, then you can use the Solver to find that root and then use synthetic division to reduce the 3rd order polynomial to a 2nd order polynomial, at that point you can now use the Quadratic Solver of the WP 34s and find the remaining complex roots.

So yeah theres still a way to get your answer even if you dont have the complex solver library, but it is a lot more painful.

On the other hand these solvers are extremely useful when you need to find solutions for any other type of equations, and specially useful for stuff like trascendental equations, in this regard the same off the shelf Casios that solve 3rd order polynomials are completely useless, so the bottomline is that the Solver function has its pros and cons.

Apparently there are programs available which address these issues on the 34s, but you need the dreaded flash cable to load them, something I have yet to build.

Something you should definitely check out is the integration solver, I loved how it will display the current calculated value in each iteration step, also the differentiate and 2nd derivative functions are extremely useful.

(05-28-2015 04:03 AM)Marcio Wrote:  Nice!

I am still studying the solver function as it seems to require a bit more attention than I expected. It seems the algorithm running it is somewhat similar to the false position method, which works very nicely but requires you to provide the interval/limits in which a particular root must be.
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Messages In This Thread
WP 34S Solver - AnalogJoe - 05-26-2015, 07:36 PM
RE: WP 34S Solver - Dieter - 05-26-2015, 07:58 PM
RE: WP 34S Solver - fhub - 05-26-2015, 08:43 PM
RE: WP 34S Solver - Dieter - 05-26-2015, 08:49 PM
RE: WP 34S Solver - fhub - 05-26-2015, 09:02 PM
RE: WP 34S Solver - AnalogJoe - 05-26-2015, 09:06 PM
RE: WP 34S Solver - Tim Wessman - 05-26-2015, 08:22 PM
RE: WP 34S Solver - AnalogJoe - 05-26-2015, 09:04 PM
RE: WP 34S Solver - Tim Wessman - 05-26-2015, 09:13 PM
RE: WP 34S Solver - AnalogJoe - 05-26-2015, 09:18 PM
RE: WP 34S Solver - emece67 - 05-27-2015, 09:08 AM
RE: WP 34S Solver - Thomas Klemm - 05-26-2015, 09:18 PM
RE: WP 34S Solver - rprosperi - 05-26-2015, 10:51 PM
RE: WP 34S Solver - Marcio - 05-27-2015, 12:17 AM
RE: WP 34S Solver - AnalogJoe - 05-27-2015, 04:26 AM
RE: WP 34S Solver - Marcio - 05-27-2015, 05:16 PM
RE: WP 34S Solver - AnalogJoe - 05-28-2015, 03:44 AM
RE: WP 34S Solver - Marcio - 05-28-2015, 04:03 AM
RE: WP 34S Solver - AnalogJoe - 05-28-2015 04:19 AM
RE: WP 34S Solver - Marcio - 05-28-2015, 04:27 AM
RE: WP 34S Solver - Pascal - 05-28-2015, 03:52 PM
RE: WP 34S Solver - Marcio - 05-28-2015, 06:07 PM
RE: WP 34S Solver - Dieter - 05-28-2015, 11:58 AM
RE: WP 34S Solver - Marcio - 05-28-2015, 12:45 PM
RE: WP 34S Solver - Paul Dale - 05-27-2015, 09:57 AM



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