simple problems
On Dec 6, 2007 3:26 PM, marciarr <marcia.rocha at gmail.com> wrote:
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)) ?
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)