On 16/11/2012, Rolf Turner <rolf.tur...@xtra.co.nz> wrote: > > Your question makes little sense. Functions have derivatives --- at > least some of them do. Data sets do not have derivatives. The > functions D(), deriv() etc. work on specified analytic expressions > for functions --- data sets do not come into the picture. >
Is the following procedure correct: Plot data from data set. Suppose the resultant graph was linear. The function could be y=mx+c, so the R function 'lm' could be applied to fit a linear line. The example in the manual for the help file '?D' shows: dx2x <- deriv(~ x^2, "x") ; dx2x So for this example it would be correct to write: functionname<-deriv(~mx+c,"x");dx2x What is the significance of ';dx2x'? It would be appreciated to be referred to the relevant manual sections, thanks. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.