Equation solvers, HP 41CV etc.

[Dieter]

(12-03-2017 03:31 AM)Trond Wrote:  I just realized that HP 41CV (which I just ordered, and still waiting for) does not have an equation solver. Eeep! OK no worries, I think I found a simple program for it here, but people also talk about a module for this. Which module would that be, and is it otherwise recommended?

There are countless root solvers available for the HP41 series. Even the standard applications booklet that came with the calculator included such a program. And of course the Math ROM (or the combined Math/Stat ROM) feature this.

About the same time the HP41 was introduced, the HP34C was the first calculator with a dedicated Solve function, which was explained in detail in the manual. The same is true for the later 15C. Since the 41-series, being the top-of-the-line models at that time, lacked this feature, HP introduced the Advantage Pac. This ROM module included a Solver that seems to use the same algorithm as the ones in the 34C or 15C. And, most important, this is not a regular user code program like the ones in the Math ROM or the Standard Pac, it is written in HP41 machine code. So you cannot copy and modify it by means of the COPY command, but it runs faster, and it uses the state-of-the-art HP-Solve algorithm.

The Advantage Pac seems to be something that offers many benefits to HP41 users. The price of a used ROM module reflects this. If you can, get one.

(12-03-2017 03:31 AM)Trond Wrote:  I am fine with with either 32SII (entering equations more or less as they look on paper) or 42S style (entering equation in RPN =0 ). I am guessing the latter would be the 41C way of doing it.

Yes. The Advantage Pac's solver expects two initial guesses in X and Y and the name of the program to solve in Alpha.

(12-03-2017 03:31 AM)Trond Wrote:  Bonus question: which HP calculators from the 70s have equation solvers? Looks like 34C has, but does HP 65/67 have this?

No, this was a HP34C first. Since it appeared in 1979 there are no other calculators of the seventies with this feature.

Well... the TI58/59 Standard ROM (Master Library module ML-01) that came with the calculator also had a – yet very simple – equation solver. So one can argue if this counts as a calculator feature. If it does this would also apply to the HP67 and others where a solver program was delivered on magnetic cards. ;-)

Dieter