[R] a symbolic derivative question, please

Erin Hodgess erinm.hodgess at gmail.com
Fri Jan 9 19:37:17 CET 2015


Ah!  Ok....thanks very much!

Sincerely,
Erin


On Fri, Jan 9, 2015 at 1:09 PM, Richard M. Heiberger <rmh at temple.edu> wrote:

> `[` is a function.  So the deriv program is seeing
>
> `[`(y,3)*r1 + r2
>
> > letters[5]
> [1] "e"
> > `[`(letters, 5)
> [1] "e"
>
> On Fri, Jan 9, 2015 at 12:31 PM, Erin Hodgess <erinm.hodgess at gmail.com>
> wrote:
> > Hello!
> >
> > I have the following:
> >
> > zzz <- expression(y[3]*r1 + r2)
> > deriv(zzz,c("r1","r2"))
> > Error in deriv.default(zzz,c("r1","r2")) :
> >    Function '`[`' is not in the derivatives table
> >
> > What am I missing, please?  Since y is not one of the variables that is
> > being "acted upon", why is the [] an issue, please?
> >
> > Thank you for any help!
> >
> > Sincerely,
> > Erin
> >
> >
> > --
> > Erin Hodgess
> > Associate Professor
> > Department of Mathematical and Statistics
> > University of Houston - Downtown
> > mailto: erinm.hodgess at gmail.com
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
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>



-- 
Erin Hodgess
Associate Professor
Department of Mathematical and Statistics
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com

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