[R-sig-teaching] Plot f(x) = x^(1/5)

[jim holtman]

this is where you should be using parenthesis to make sure you have the
correct precedence of operations:

> -0.5^(1/5)
[1] -0.8705506
> (-0.5)^(1/5)
[1] NaN
>
> x <- -0.5
> x^(1/5)
[1] NaN
>



Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

On Tue, May 17, 2016 at 9:09 AM, David Pell <David.Pell at mrc-hnr.cam.ac.uk>
wrote:

> Try :
>
> -0.5^(1/5)
> [1] -0.8705506
>
> David
>
>
> -----Original Message-----
> From: R-sig-teaching [mailto:r-sig-teaching-bounces at r-project.org] On
> Behalf Of Steven Stoline
> Sent: 17 May 2016 14:07
> To: jim holtman <jholtman at gmail.com>
> Cc: R-sig-teaching <r-sig-teaching at r-project.org>
> Subject: Re: [R-sig-teaching] Plot f(x) = x^(1/5)
>
> Dear All:
>
> in my TI-Calculator (-0.5)^(1/5) = -0.8705, but in R (-0.5)^(1/5) = NaN.
>
>
> with thanks
> steve
>
> On Tue, May 17, 2016 at 8:52 AM, jim holtman <jholtman at gmail.com> wrote:
>
> > System is working correctly. A negative number cannot be raised to a
> > fractional power:
> >
> > > (-2)^(1/5)
> > [1] NaN
> >
> >
> >
> >
> > Jim Holtman
> > Data Munger Guru
> >
> > What is the problem that you are trying to solve?
> > Tell me what you want to do, not how you want to do it.
> >
> > On Tue, May 17, 2016 at 8:44 AM, Steven Stoline <sstoline at gmail.com>
> > wrote:
> >
> >> Dear All:
> >>
> >>
> >> I am trying to plot the function f(x) = x^(1/5) for x=seq(-2,2,0.01).
> >> It give me only the plot of f(x) for the positive part of x. I
> >> checked the values of f(x), it is NaN for all negative values of x.
> >>
> >> *this is my code:*
> >>
> >>
> >> x<-seq(-2,2,0.01)
> >> y<- (x)^(1/5)
> >> plot(x,y, type="l", lwd=3, xlab = " ", ylab = " ", col="blue")
> >> abline(v=0, col="gray", lty=2, lwd=3) abline(h=0, col="gray", lty=2,
> >> lwd=3)
> >>
> >>
> >>
> >> any help will be appreciated.
> >>
> >>
> >> with many thanks
> >> steve
> >> --
> >> Steven M. Stoline
> >> 1123 Forest Avenue
> >> Portland, ME 04112
> >> sstoline at gmail.com
> >>
> >> [[alternative HTML version deleted]]
> >>
> >> _______________________________________________
> >> R-sig-teaching at r-project.org mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-sig-teaching
> >>
> >
> >
>
>
> --
> Steven M. Stoline
> 1123 Forest Avenue
> Portland, ME 04112
> sstoline at gmail.com
>
> [[alternative HTML version deleted]]
>
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