Calculators with equation storage and multi-letter variable names

[Dave Britten]

I'm trying to find calculators - of any brand - that allow storing algebraic equations containing variables that are more than just a single letter. Bonus points if they let you solve numerically for any variable rather than just evaluating the expression. I know there was a similar discussion on this board a while ago (and which I couldn't find) regarding current calculators that can store equations, but I'm also interested in older models that have this capability.

Some that I know of that can store equations and solve for any variable:

HP 18C, 17BII, 19BII, 27S, etc. - These all have the HP solver which is probably the best implementation of this functionality.
HP 28C, 28S, 48-50 - I believe these all have an equation solver, don't they?
TI-67
TI-85, TI-86
TI-92, TI-89, Voyage 200
Sharp EL-9300 - Uppercase letters are single-letter global variables, lowercase letters can be used for multi-letter temporary variables. Strangely, all their later graphing calculators removed the lowercase temporary variable feature.
Casio Classpad - I'm pretty sure these have this capability.
HP Prime

A few more limited ones:

TI-68 - I think you can use up to 3 letters for a variable name, though it only evaluates and doesn't solve for any variable.
Sharp EL-5120 - Allows for two-character variable names consisting of one letter and one digit. Can solve for any variable.
Sharp PC-1260, PC-1261, PC-1262 - Stores and evaluates equations, but no solver.
Casio fx-5800P - Can store and evaluate equations with two-character variable names. Solver can only be used on equations with single-letter variables.
Casio fx-5000F, fx-1000F - Stores equations with two-character variables (like the fx-5800P), but no numeric solver.

Close but no cigar:

HP 32SII, 33S, 35S, 22S - Stores algebraic equations that can be evaluated or solved, but single-letter variables only.
Sharp EL-9400, EL-9600, EL-9900 - Basically the same as the EL-9300, but single-letter variables only.

Anything else to add to the list?

[Hollerith]

The TI Galaxy 67 has names for programs, formlae, labels and variables that can be up to 6 characters in length. It has a solver for formulae.

It was introduced in 1992, 3 years after the TI-68. It is a nice calculator to use.

Brian M

[Dave Britten]

(12-20-2021 11:43 PM)Hollerith Wrote:  The TI Galaxy 67 has names for programs, formlae, labels and variables that can be up to 6 characters in length. It has a solver for formulae.

It was introduced in 1992, 3 years after the TI-68. It is a nice calculator to use.

Brian M

Oh yeah, forgot about that one, thanks. Sounds like a model I should try to track down.

[celltx]

Casio 9750GIII and CG50 both have a nice solver that solves for any variable. However variables names have only one letter.

On the positive side, Casio has a powerful e-Activity applications that basically integrates all other applications, including the solver, with a notepad-like text interface. So, even though you can't have long variable names, you can put a descriptive text that explains their meaning in a specific context A single e-Activity doc can have as many solver stripes inside as you want and not limited by 20 equations like in HP Prime. One can have many e-Activity docs too. Very useful integration feature.

[Dave Britten]

(12-21-2021 07:27 PM)celltx Wrote:  Casio 9750GIII and CG50 both have a nice solver that solves for any variable. However variables names have only one letter.

On the positive side, Casio has a powerful e-Activity applications that basically integrates all other applications, including the solver, with a notepad-like text interface. So, even though you can't have long variable names, you can put a descriptive text that explains their meaning in a specific context A single e-Activity doc can have as many solver stripes inside as you want and not limited by 20 equations like in HP Prime. One can have many e-Activity docs too. Very useful integration feature.

Yeah, I've done that a few times myself! It's a nice way to put that otherwise unused e-Activity application to some use.