How do i find where 2 best fit lines cross?

Hi
I was wondering if anyone knows a way to find where 2 best fit lines cross, I don't have the equation for the lines and i'm not sure if I can get it.
I currently have the program tracing the lines and comparing y values however it will only increment in steps of 0.1 on the x-axis and i need an accuraccy of 0.0001

If you have or can get a series of XY value pairs for both of the lines, getting the equation of the line is as simple as calling Linear Fit.vi. Once you have the equations of both lines, the intersection is simple algebra, subject to the accuracy of your fit. If the XY data pairs describe a curve, not a line, and you want more accuracy, you can try a polynomial fit using General Polynomial Fit.vi. To find the intersection, set one polynomial equation equal to the other, compute the coefficients of the resulting polynomial equation, and find the root using Polynomial Roots.vi. All this assumes you have a Pro or better version of LabVIEW. If you don't, you can still do it, but you will need to write some code for the fits and roots. Check out a copy of Numerical Recipes in C, by Press et. al. from your local library and it will give you the equations for all the above. With LabVIEW's native matrix handling capabilities, the rest is straighforward.
Let us know if you need more help.
This account is no longer active. Contact ShadesOfGray for current posts and information.

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The named functions are not available in AppleWorks.
One way to mimic them is to use AppleScripts .
Here is an old one which calculate the slope.
--{SCRIPT}
tell application "AppleWorks 6"
activate
tell front document
set laSelection to get object specifier of the selection
set debutCible to name of first cell of laSelection
-- nom de la première cellule cible
-- • name of first dest cell
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set cell12 to name of row dernRangee of column premColonne
set cell21 to name of row premRangee of column dernColonne
set cell22 to name of row dernRangee of column dernColonne
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on calcule(nb_)
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activate
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set formula of cell "D1" to "=A1^2"
select cell ("C1..D" & nb_)
select menu item 3 of menu 5 (* Recopier vers le bas
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--{/SCRIPT}
Yvan KOENIG (from FRANCE mercredi 1 août 2007 06:51:46)
edit:
When I edit my message, the script appears but when I look in the forum it doesn't appear.
It appears that it is a recent "feature" of this forum;
I made a last attempt.
If it doesn't work, you may send a mail to
koenig then a dot then yvan then an @ then tele2 then a dot then fr
I will send you the script as a mail attachment.
Yvan KOENIG (from FRANCE mercredi 1 août 2007 07:07:17)
Message was edited by: KOENIG Yvan

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