Inverting a linear function is easy, and more generally functions need not
be invertible. But uniroot() is very helpful in finding an inverse of a
monotonic function, and the idea is used in some of the qxxxxx functions.
On Fri, 26 Jan 2007, phwang2000 at ucla.edu wrote:
> Hi,
>
> I wrote a simple derivative program
>
> (ftest=deriv(y~x^2, c("x"), function(x){} ))
>
> I put (ftest=deriv(y~x^2, c("x"), function(x){} ))(1) which
return 2
> which is correct.
>
> however, if I want the output to be 0 and hopefully a new inverse
> function can take in output (2) and return x=1. Can this be
> accomplished. Maybe output(0) can return x=0
>
> Thanks
> pat
>
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--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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