Hi, i am using ti89.

Is there a way to put results for x1 and x2 in a variable?

Result of solve(x^2=4,x) is string:
"x=-2 and x=2"

Thanks.

Use left( and right(

Hey, I learned something new too, thanks DrDnar! I didn't realize that you were a 68k connoisseur as well as a z80 enthusiast.

Problem is, that for example result x1 can be an integer and x2 can be a number with decimal component.

It could work with mid() and right() but it's a bit messy.

Code:


I am not sure if this code will work in all cases. It depends on Exponetial format and Exact/Approx mode, but i can set those.

Edit: Solve() actually returns expression so i have to convert it into string, before i can extract what i need. For now, this is working for me.

The part( function may help. It's essentially a parsing tool.

solve(x^2=4,x) returns x=2 or x=-2

part(solve(x^2=4,x)) returns 2, the number of arguments to the top-level function/operator in the expression.

To get each of these two arguments:
part(solve(x^2=4,x),1) returns x=2
part(solve(x^2=4,x),2) returns x=-2

To get the top-level function:
part(solve(x^2=4,x),0) returns “or”

This can be applied recursively to parse the rest of the expression, for example:

part(solve(x^2=4,x),1)→a [returns x=2 and stores the expression into a]
part(a) returns 2
part(a,1) returns x
part(a,2) returns 2
part(a,0) returns “=”

You could use this to make a subprogram or function that searches for the values and puts them in a list, or something like that.

I think this is one answer to the question. The method works for me. I am posting the answer I received from the respondent indicated below. Couldn't write the "store" symbol in the message below, so just used the word:

"What about, e.g., nsolve(5=2+x,x) store y
This will perform a numeric solve on 5=2+x and store the result (3) in y. I was mistaken about it returning an equation--the symbolic solve command does this, but the numeric nsolve just returns a straightforward value.

--
Travis Evans
The ticalc.org Project
http://www.ticalc.org/"►

Why did not use zeros() result will be a matrice and can be manipulate! If have this function in that calculator. Im presume is like a Ti-Nspire which I have it and try to found resolve this problem while ago. I hope can help.

PS: if u use solve and find a equation with more than one solution, e.g. 3 or 4 what u want to do to extract it the roots!?

I believe that the original question was about the TI-89, but since I have no idea about that calculator and it's similarities to the Nspire, I won't try to help out with it.