R help - May 2011 - about vector to the power of a decimal

Hi
why I can't do this?
m<-c(1,-2,3)
m^2.1
with a negative number in it ,but I can do this to a single negative number like
-2^2.1~
Thank you ~
 
 
JIngsi
	[[alternative HTML version deleted]]

Please take a look at FAQ 7.33 
(http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-are-powers-of-negative-numbers-wrong_003f)

Basically, what you're really calculating is
> -(2^2.1)
[1] -4.287094

You can't raise a negative number to a fractional power, unless
you specify it as a complex number
> (-2)^2.1
[1] NaN
> complex(real=-2)^2.1
[1] 4.077269+1.324785i


 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Fri, 13 May 2011, ??? wrote:
> Hi
> why I can't do this?
> m<-c(1,-2,3)
> m^2.1
> with a negative number in it ,but I can do this to a single negative number
like -2^2.1~
> Thank you ~
>
>
> JIngsi
> 	[[alternative HTML version deleted]]
>
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