extraction of roots in R

If you just want the nth root of X, use X^(1/n)

x <- 256
x^(1/8)

[1] 2

x <- -256
x^(1/8)

[1] NaN

It appears that you get the positive real root.

Is this all you wanted?


On 1-Nov-13, at 11:11 AM, Gary Dong wrote:

Dear R users,

I wonder if R has a default function that I can use to do  
extraction of
roots.

Here is an example:

X                  N
2.5              5
3.4              7
8.9              9
6.4              1
2.1              0
1.1             2

I want to calculate Y = root(X)^N, where N represents the power.  
what is
the easy way to do this?

Thank you!

Gary

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Don McKenzie
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Professor
School of Environmental and Forest Sciences
University of Washington

dmck at uw.edu