From: Gabor Grothendieck <ggrothendieck_at_gmail.com>

Date: Thu, 6 Dec 2007 17:40:04 -0500

> Hello R users,

*> I have been looking through Help files and Nabble list for the answers for
*

*> these simple questions, but it seems to be fruitless.
*

*> 1- in a data frame with two columns, x and y, how do I get the corresponding
*

*> value of x to, let's say, the minimum value of the y column (min (data$y)) ?
*

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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 Thu 06 Dec 2007 - 22:46:27 GMT

Date: Thu, 6 Dec 2007 17:40:04 -0500

On Dec 6, 2007 3:26 PM, marciarr <marcia.rocha_at_gmail.com> wrote:

>

> Hello R users,

In the builtin Formaldehyde data frame find the value of carb (first column) which corresponds to the least value of optden (second column):

with(Formaldehyde, carb[which.min(optden)])

> 2- how do I solve a simple equation? Considering the equation y= exp(-x)^12,

*> I would like to find the values of x for, for example, y=0.01, so
**> exp(-x)^12=0.01. How do I do that using R?
**> I know those a probably very, very simple questions, but for which I do not
**> seem to find the answer.
*

Search between 0 and 1 for the root of the indicated function:

uniroot(function(x) 0.1 - exp(-x)^12, 0:1)

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