Look at this: > x <- as.complex(-4) > x [1] -4+0i > x^(1/3) [1] 0.793701+1.37473i > (-4)^(1/3) [1] NaN
It seems that R gives you the principal root, which is complex, and not the real root. Kjetil On Tue, Oct 26, 2010 at 8:05 PM, Gregory Ryslik <rsa...@comcast.net> wrote: > Hi, > > This might be me missing something painfully obvious but why does the cube > root of the following produce an NaN? > >> (-4)^(1/3) > [1] NaN >> > > As we can see: > >> (-1.587401)^3 > [1] -4 > > Thanks! > > Greg > ______________________________________________ > R-help@r-project.org mailing list > 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. > ______________________________________________ R-help@r-project.org mailing list 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.