[R] How to provide a result from D(f(x), "x") to a curve(f'(x)) ???

[Greg Snow]

Try this:

> tmp <- as.function(list(x=NULL, D( expression( x^3 ), 'x' ) ) )
> curve(tmp)

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Walmes Marques Zeviani
> Sent: Wednesday, February 17, 2010 11:32 AM
> To: r-help at r-project.org
> Subject: [R] How to provide a result from D(f(x), "x") to a
> curve(f'(x)) ???
> 
> 
> Hi all,
> 
> I want to provide the result from D() to curve(), because I want to
> plot the k-th derivative of some functions. Actually, I copy from
> console the result given by D() and paste inside curve(). With a lot of
> functions and high degree differentiation this process is tedious. Can
> I provide directly??
> 
> # what I actually have done (very simple function)
> D(expression(x^3), "x") # copy this result
> curve(3 * x^2) # paste inside
> 
> # my failed attempts
> curve(as.expression(D(expression(x^3), "x")))
> curve(as.character(as.expression(D(expression(x^3), "x"))))
> curve(noquote(as.character(as.expression(D(expression(x^3), "x")))))
> 
> Thanks in advance.
> Walmes Zeviani, Brasil.
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