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From: Angus Hammond on 29 May 2010 15:56
Is there a way to get an accurate square root?
This means that a negative number should return the appropriate complex
number. I have been having some trouble with this in a program that
solves quadratic equations recently. Ideally but not necessarily it
should be able to get the square root of complex numbers as well.
NB Neither -2**0.5 or Math::sqrt(-2) return appropriate answers. (-2 and
an error respectively)
Thanks in advance.

From: Jean-Julien Fleck on 29 May 2010 16:03
Hello Angus,

2010/5/29 Angus Hammond <angushammond(a)hotmail.co.uk>:
> Is there a way to get an accurate square root?
> This means that a negative number should return the appropriate complex
> number. I have been having some trouble with this in a program that solves
> quadratic equations recently. Ideally but not necessarily it should be able
> to get the square root of complex numbers as well.
> NB Neither -2**0.5 or Math::sqrt(-2) return appropriate answers. (-2 and an
> error respectively)

require 'complex'
include Math
c = Complex(-2,0)
sqrt(c)

>> require 'complex'
=> true
>> include Math
=> Object
>> c = Complex(-2,0)
=> Complex(-2, 0)
>> sqrt(c)
=> Complex(0.0, 1.4142135623731)

Cheers,

--
JJ Fleck
PCSI1 Lycée Kléber

From: Angus Hammond on 29 May 2010 16:33
Thanks I had tried require complex and Math::sqrt but only separately.
Thanks again.
Angus

On 29/05/10 21:03, Jean-Julien Fleck wrote:
> Hello Angus,
>
> 2010/5/29 Angus Hammond<angushammond(a)hotmail.co.uk>:
>
>> Is there a way to get an accurate square root?
>> This means that a negative number should return the appropriate complex
>> number. I have been having some trouble with this in a program that solves
>> quadratic equations recently. Ideally but not necessarily it should be able
>> to get the square root of complex numbers as well.
>> NB Neither -2**0.5 or Math::sqrt(-2) return appropriate answers. (-2 and an
>> error respectively)
>>
> require 'complex'
> include Math
> c = Complex(-2,0)
> sqrt(c)
>
>
>>> require 'complex'
>>>
> => true
>
>>> include Math
>>>
> => Object
>
>>> c = Complex(-2,0)
>>>
> => Complex(-2, 0)
>
>>> sqrt(c)
>>>
> => Complex(0.0, 1.4142135623731)
>
> Cheers,
>
>


From: jzakiya on 2 Jun 2010 12:45
On May 29, 3:33 pm, Angus Hammond <angushamm...(a)hotmail.co.uk> wrote:
> Thanks I had tried require complex and Math::sqrt but only separately.
> Thanks again.
> Angus
>
> On 29/05/10 21:03, Jean-Julien Fleck wrote:
>
> > Hello Angus,
>
> > 2010/5/29 Angus Hammond<angushamm...(a)hotmail.co.uk>:
>
> >> Is there a way to get an accurate square root?
> >> This means that a negative number should return the appropriate complex
> >> number. I have been having some trouble with this in a program that solves
> >> quadratic equations recently. Ideally but not necessarily it should be able
> >> to get the square root of complex numbers as well.
> >> NB Neither -2**0.5 or Math::sqrt(-2) return appropriate answers. (-2 and an
> >> error respectively)
>
> > require 'complex'
> > include Math
> > c = Complex(-2,0)
> > sqrt(c)
>
> >>> require 'complex'
>
> > =>  true
>
> >>> include Math
>
> > =>  Object
>
> >>> c = Complex(-2,0)
>
> > =>  Complex(-2, 0)
>
> >>> sqrt(c)
>
> > =>  Complex(0.0, 1.4142135623731)
>
> > Cheers,
>
>

FYI. For more extensive (and easy) way to add the ability
to find the nth roots of all numerical types check out
my Roots module here:

http://gist.github.com/422636

Jabari
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