This smells like homework, which the Posting Guide indicates is off topic. I am not aware of "the function" that will solve this, but if you know what a gradient is analytically then you should be able to put together a solution very similar to the code you already have with the addition of using the coef function. -- Sent from my phone. Please excuse my brevity.
On April 5, 2018 3:44:03 AM PDT, g l <gnuli...@gmx.com> wrote: >Readers, > >Data set: > >t,c >0,100 >40,78 >80,59 >120,38 >160,25 >200,21 >240,16 >280,12 >320,10 >360,9 >400,7 > >graphdata<-read.csv('~/tmp/data.csv') >graphmodeld<-lm(log(graphdata[,2])~graphdata[,1]) >graphmodelp<-exp(predict(graphmodeld)) >plot(graphdata[,2]~graphdata[,1]) >lines(graphdata[,1],graphmodelp) > >Please what is the function and syntax to obtain gradient values for >the model curve at various requested values, e.g.: > >when graphdata[,1] at values = 100, 250, 350 ? > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.