[R] Obtain gradient at multiple values for exponetial decay model

[Jeff Newmiller]

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 <gnulinux using 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 ?
>
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