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HP 35s and Solve button (but not in equation catalogue)
10-01-2014, 01:09 AM
Post: #12
RE: HP 35s and Solve button (but not in equation catalogue)
(09-30-2014 06:27 PM)Dieter Wrote:  
(09-30-2014 11:52 AM)mcjtom Wrote:  When I try to wrap function in programme, I get SOLVE ACTIVE message. What do I do from there?

Simple - avoid the error. ;-) The message means that you use Solve (or Integrate, for that matter) within a program that is being solved.

Quote:Here is the programme:

A001 LBL A
A002 FN= A
A004 RTN
B001 LBL B
B002 PxV=NxRxT
B003 RTN

I invoke it by XEQ A.

There is your error. You start the program at label A which then tries to solve itself (FN=A). This obviously makes no sense. You even want to solve for an unknown variable B which is not used anywhere.

Please keep in mind:

"FN=A" defines the function/program at label A as the one that is to be solved.
"SOLVE B" defines variable B as the one you want to know.

Here is an example for a correctly working program:

A001 LBL A
A002 FN=B ; solve the equation following label B
A003 SOLVE N ; and solve it for variable N (or P, or V, or R, or T)
A004 VIEW N ; display result (required within a program)
A005 RTN

B001 LBL B ; here is your program/equation
B002 PxV=NxRxT ; with these five variables P, V, N, R and T
B003 RTN

Please note the additional VIEW N statement in A004 that displays the result obtained by Solve. Within a program it is not displayed automatically. Simply because you may want to continue with that result instead of having it displayed. Within a program, Solve also works like a test command: if there is a result, the program continues with the next statement. If no result can be calculated, the next step is skipped (!).

(09-30-2014 11:52 AM)mcjtom Wrote:  Maybe SF 11 has something to do with it, but I wasn't able to successfully use it...

Flag 11 does not make a difference here. It just decides whether you are prompted for the variables or not. With flag 11 cleared you can use a sequence of INPUT statements (one for each variable) at the beginning of the program defining your function, and you will be asked for the known variables – cf. chapter 15 of the 35s manual.


An excellent and clear explanation Dieter! This was quite confusing when I first started using it, and took a while to figure it out. Yours is by far the best explanation of this I've seen. Thanks very much for taking the time to explain it so clearly, including useful tips like the test command behavior.

--Bob Prosperi
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RE: HP 35s and Solve button (but not in equation catalogue) - rprosperi - 10-01-2014 01:09 AM

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