HELP: Need a jump start equation back solver

[rmsmith1126]

I'm coming from an HP-50g and HP-42s mentality, and I just got my son an HP Prime G2 for school in the Fall.

HP used to have the best technical writers for their manuals especially the Advanced User Guide. The latest docs are awful; the examples are even worse IMHO.

I have a sample equation:
'q = 0.65 * SQRT( 64.348 * ( h - 0.5 * o )) * o * w * n'

The variables used to be presented as softkeys:
[q] [h] [o] [w] [n]

I need someone to jump start me with working PPL code using the above equation with the variables in the Form format (or soft keys) with back solve capability like the TVM in the Finance app.

Thanks in advance!

[trojdor]

I would personally just use the solver app. (the big orange Solve button on the Apps screen....NOT the linear solver next to it)
Save the programming for something complicated/unusual.

I think the numeric solver will do everything you need w/out writing any code.
Enter the equation pretty much as you've written it (in Symbolic view).
Make sure you've got a check mark next to the equation you want to solve, and switch to numeric view. (the button under Plot).
Enter the know variables....solve for the remaining unknown.
Done.

[rmsmith1126]

(06-14-2021 07:08 AM)trojdor Wrote:  I would personally just use the solver app.

I have 25 sites each using different sized variables. So maybe I could create a list of equations stored in L1, query the appropriate one with POS() and insert it into the equation variable E1. It looks like the INPUT() command is capable of a titled list by number.

The HP-50g with its sub-folders was awesome because all of the previous equations and results were stored in separate variables within each sub-folder. Kudos to the team who created the HP-RPL language and dynamic stack.

Thanks for the follow-up!

[BruceH]

Not quite sure what you mean by "I have 25 sites using different sized variables" but if you have more than 10 expressions and need more than the 10 rows of the Solver App then simply save a copy of it.

To do this press Apps, select Solver (but don't start it), and one of the menu options is Save. Press this and give it a new name "Solver2" for example.

Now you see Solver and Solver2 in your list of apps. Solver2 starts out as a copy of Solver but any changes you make are independent so you can have another 10 expressions.

Repeat once more to create Solver3 and you now have space for 30 expressions.