Showing my age, but when I went to school I had HP scientific (28S and 48SX) calculators. Now my kids are using the nSpires and I wanted to help them out on some problems. One of the features I used constantly on my HP was the Solver. With it you could type in an equation (ex. a^2 + b^2 = c^2) and store it as a name in the Solver. You could then pull up that equation and the variables would show up on the screen just above some physical input buttons. I could type something like 3 and then hit the button under the a to store the value of 3 in the variable a, and then a 5 and the button under the c to store the value of 5 in the variable c

. I would then hit the button under the b (I think I had to have the 'shift' key pressed so that the calc knew I was not inputting a value but was requesting a value) and the calculator would do the math and return a 4.

What I liked about this was that I could have the base equation, but then solve for any of the variables (providing I gave it enough info to solve).

Thinking such an 'old school' and useful capability must exist in the newer calcs, I have been searching the web for this ability. It seems the answer is that the nSpires do not have this type of ability, at least built in. I that correct? If not, please let me know.

So, where I think that takes me is to programming. I'm a programmer, but my kids are not, unfortunately. I don't have their calculators on hand to test, but it seems like I could create a function that uses solve(). Do you think something like this would work? (First, I have not programmed the nSpire yet, so there are probably some syntax errors, but I think you will see what I am trying to do).

```
Define pythag(a, b, c) =
Func
return solve(a^2 + b^2 = c^2, x)
endfunc
```

So, to solve for b, I would type something like this:

pythag(4, x, 5)

where x is my unknown.

Will the nSpire be 'smart' enough to handle the integer and character input? Any other ideas?

Thanks,

Pauley