Re: (-8)^(1/3)
- To: mathgroup at smc.vnet.net
- Subject: [mg31321] Re: (-8)^(1/3)
- From: "David W. Cantrell" <DWCantrell at sigmaxi.org>
- Date: Sun, 28 Oct 2001 03:07:00 -0500 (EST)
- References: <9rdg8k$7p7$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"David Park" <djmp at earthlink.net> wrote: > LuisMa, > > Needs["Miscellaneous`RealOnly`"] > > (-8)^(1/3) > -2 > > Ted Ersek has a nice package on MathSource called SwitchableRealOnly. It > works somewhat better than RealOnly and also allows you to turn RealOnly > on and off without having to kill the kernel. Yes, this is basically the only way that you'll get _literally_ (-8)^(1/3) to return -2. But another option which will work, if you simply need a real cube root function, is to define your own function, perhaps named RealCbrt, to be Sign[x]*(Abs[x])^(1/3). Then RealCbrt[-8] yields -2, as desired. David Cantrell -- -------------------- http://NewsReader.Com/ -------------------- Usenet Newsgroup Service