From: kitty <kitty.a1000_at_gmail.com>

Date: Mon, 04 Apr 2011 11:35:08 +0100

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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. Received on Mon 04 Apr 2011 - 10:44:35 GMT

Date: Mon, 04 Apr 2011 11:35:08 +0100

I am trying to get the second derivative of a logistic formula, in R summary the model is given as :

but I know the formula used is

2))

*>
**> d1<-deriv(express)
*

Error in deriv.default(express) : element 2 is empty;

the part of the args list of '.Internal' being evaluated was: (expr, namevec, function.arg, tag, hessian) ####

Why is this not working and how do I get the second derivative?

Thank you for reading my post, all help is appreciated, Kitty

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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. Received on Mon 04 Apr 2011 - 10:44:35 GMT

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