[R] Inflection Points
Martin aus Chemnitz
MartinAusChemnitz at gmx.net
Thu Jul 1 17:49:57 CEST 2004
Hi!
Some weeks ago I discovered R. Now, I have a somewhat complicated task
and am not sure whether R is the right tool to solve it.
I got data of several series or measurements where I have to find the
two inflection points. I did a linear regression (with ^2 and ^3
arguments), the problem there was that I had to look only at a very
narrow band of measurement in order to get the approximation right at
the essential point. (Maybe there is a better way than lm?)
Now that I have an appromiated function, I need its inflection point,
but I could not find any R function for that. Is there any? Or can
anyone recommend a good (possibly free) mathematical programme?
Maybe this could be helpful: All the measurements look like this and I
marked the points of interest.
,-------
/
/ <--
/
,----´
/
| <--
/
-----´
Thank you very much for your help
Martin
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