From: Jim Freeze <jim@...>
Date: 2003-02-06T07:16:03+09:00
Subject: Re: Error in Complex

On Thursday,  6 February 2003 at  7:08:37 +0900, Martin DeMello wrote:
> Daniel Carrera <dcarrera@math.umd.edu> wrote:
> > Hello,
> > 
> > There seems to be a problem in Complex.  It gets (-i)^2/3 wrong.
> > 
> > 2/3
> > i    =  1/2 + sqrt(3)/2
> > 
> >   2/3
> > (-i) = - 1
> 
> -i = exp(-i * pi/2)
> (-i)^(2/3) = (1)^2/3 * exp(-i * pi/2 * 2/3)
>            = exp(-i * pi/3)
> 	   = cos(pi/3) - i sin(pi/3)
> 	   = 1/2 - sqrt(3)/2
> 
> martin
 
require 'complex'
=> true
irb(main):005:0> Complex(0.0,1.0)**(2.0/3.0)
=> Complex(0.5000000000000001, 0.8660254037844386)

Looks ok to me.

-- 
Jim Freeze
----------
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	A person of low taste, more interested in himself than me.
		-- Ambrose Bierce, "The Devil's Dictionary"