R help - Nov 2013 - extraction of roots in R

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

	[[alternative HTML version deleted]]

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
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting- 
> guide.html
> and provide commented, minimal, self-contained, reproducible code.




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