[R] how to fit exponential curve such as a*b^t in r?

[Berend Hasselman]

On 16-12-2013, at 08:52, 水静流深 <1248283536 at qq.com> wrote:

> input <- "    
>      t    y    
>     1  5.3    
>     2  7.2    
>     3  9.6    
>     4 12.9    
>     5 17.1    
>     6 23.2"         
>    dat<-read.table(textConnection(input),header=TRUE,sep="")    
>    t<-dat[,1]    
>    y<-dat[,2]   
> 
> `y=3.975*(1.341^t)` is the resule of fit,how can i use `nls` function to get it?


Have you looked at ?nls.
Have you simply tried

nls(y~a*b^t,data=dat)

You can also do a linear regression  on  log(y) ~ A + B* t.
And afterwards transform to the original coefficients.

Berend

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