Re: a simplification problem
- To: mathgroup at smc.vnet.net
- Subject: [mg55234] Re: [mg55172] a simplification problem
- From: DrBob <drbob at bigfoot.com>
- Date: Thu, 17 Mar 2005 03:29:20 -0500 (EST)
- References: <200503161035.FAA23728@smc.vnet.net>
- Reply-to: drbob at bigfoot.com
- Sender: owner-wri-mathgroup at wolfram.com
That's not a simplification; it's the wrong answer. Here's the right one (based on the commonly used "branch" of the exponential):
ComplexExpand[(-1)^(1/3)]
1/2 + (I*Sqrt[3])/2
If you mean, "How do I extract the real third root of -1?", here's a method:
ComplexExpand[x /. Solve[x^3 == -1]]
{-1, 1/2 + (I*Sqrt[3])/2, 1/2 - (I*Sqrt[3])/2}
First@Select[%, FreeQ[#1, Complex] & ]
-1
Bobby
On Wed, 16 Mar 2005 05:35:49 -0500 (EST), Hui Fang <fangh73 at xmu.edu.cn> wrote:
> Dear All,
>
> My questions is simple:
> How do I simplify (-1)^(1/3) to -1?
>
> Thanks!
>
>
>
>
--
DrBob at bigfoot.com
- References:
- a simplification problem
- From: Hui Fang <fangh73@xmu.edu.cn>
- a simplification problem