In praise of hp 15c :-)


I really love the 15c: layout, keyboard feeling and colors. But with the 32/42 solver



I second you, Lion.

What's wrong with the 15C's solver? Lack of ALPHA messages? Speed? I just want to know what bothers you, my friend! >8-D

If you want more precision, you need more internal digits, and the HP15C does not have them. Unfortunately that's what could be done at that time. With the number of digits the HP15C shows the answer minus the least significant digit, I think in very fewer cases it will be different of those found by the HP32/42 solver. And I think the exceptions are so specific that almost need to be created to check the resulting error.

Best regards.

Luiz C. Vieira - Brazil


No Luiz: it is neither alpha msgs, nor precission, nor speed..

What I like of the 32/42 solver is that I can program an equation with several variables and solve the one I want. In the 15c, an specific prg is needed for each variable.



...I forgot that! :-(

Also, I used the wrong charface in my post: instead of a laughing >8-D , please see a smiling, friendly >:-).

Thank you.


Then is better to have some 11c and some 42s instead of one single 15c or not ?


Hi, Joan;

I believe the HP11C is the pre-15C, although many HP11C owners do not agree with. The HP15C has everything the HP11C has plus matrices, complex math, numerical solve and integrate. To handle most of these features, it has 448 bytes RAM user memory, that allow the user to compute the inverse of an 8X8 real matrix or a 4X4 complex matrix in one key: [1/x] (after input all data, of course). And the eight conditional tests were expanded to ten but had their key inscriptions reduced to three, leaving five places for the new features.

The HP42S ia a lot more than this. I have two HP15C and two HP42S (one of them I upgraded to 32KRAM, thanks to Randy's final guidance... I'll always mention it) and I also have an HP11C. All of them have their applicability and there are things that the HP11C can do and I use it. If I am interested in tdevelopiong a program and I want to know if it fits in an HP11C I do not need to make post considerations after loading it in an HP15C to be sure if it fits or not. I simply load it in the HP11C and run it.

What for? Sometimes for fun, sometimes as a request. I have done a lot of programming when I was at the university, in a time Voyagers, Spices, HP41 and TI58/59 used to share the space with Sharp and Casio pocket computers.

What a time, what a time...

Now we have 16's and 17's crackers breaking NASA and CIA net passwords... for fun.

What a time, what a time...


Luiz C. Vieira - Brazil


Raul wrote:

"hat I like of the 32/42 solver is that I can program an equation with several variables and solve the one I want. In the 15c, an specific prg is needed for each variable."

True, the 15C does not support explicit "choice of variables" for solve and integrate. However, there's an easy workaround: Use the I register in a general program. For example, to solve or integrate a function with variables x, y, and z:

(x) STO 1; (y) STO 2; (z) STO 3

001 LBL "A"

002 STO (i)

(use RCL 1, RCL 2, and RCL 3 each time a variable is used)

nnn RTN

Key in n STO I (n = 1,2 or 3) and STO each of the parameters (fixed variables) as above prior to executing SOLVE or INTEGRATE on the program "A".

Any numbered registers may be used; the 15C won't use your choices for its own purposes.

That having been said, the 32Sii and 42S *are* much faster number-crunchers. While the 32Sii allows equations to be solved and integrated, RPN programs run faster.


Guau! I'll try...

Thanks. Raul.


Karl...thanks!. It's great!

Raul (the Doppelgaenger ;-)

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