R help - Aug 2008 - non-linear regression problem

I need to do a non-linear regression in the form of

Y = a0 + a1 * arctan(a2 * x) + error.

A data sample (X,Y) is available, but I can't remember how to run this sort 
of regression through R so that I get a value for a0, a1 and a2.

Can someone please give me a hint?

Thank you in advance.

Hi

r-help-bounces at r-project.org napsal dne 14.08.2008 16:05:11:
> 
> I need to do a non-linear regression in the form of
> 
> Y = a0 + a1 * arctan(a2 * x) + error.
> 
> A data sample (X,Y) is available, but I can't remember how to run this 
sort 
> of regression through R so that I get a value for a0, a1 and a2.
Hi

?nls, ?optim
could be your first choice.

nls(Y ~ a0 + a1 * arctan(a2 * x), data= ...,start=list(a0= , ...), ...)

Regards
Petr
> 
> Can someone please give me a hint?
> 
> Thank you in advance.
> 
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