Thanks Sarah, All,
I guess I never thought of a negative sign as an "operation", but
knowing that it is considered an operation explains everything nicely.
Somewhere in it's underbelly, I suppose -4 is represented as "0 - 4"?
Either way, I'm glad it is consistent & accurate, so that I didn't find
myself in another pickle like "weak" typing and attempts to use time /date
classes in 'R' have brought me.
Thanks!
Mike
---
[The theory of gravity] is to me so great an absurdity that I believe no
Man who has in philosophical matters a competent faculty of thinking can
ever fall into it. -- Isaac Newton
On Wed, Mar 21, 2012 at 4:37 PM, Rolf Turner <rolf.tur...@xtra.co.nz> wrote:
> On 22/03/12 12:17, Sarah Goslee wrote:
>
>> It's order of operations, and a good reason to always use
>> parentheses: which is evaluated first, the unary minus or
>> the raising-to-powers?
>>
>> (-4)^0.5
>> -(4^0.5)
>>
>> sqrt(-4)
>> -sqrt(4)
>>
>
> If the OP *really* wants the square root of -4 he could do
> sqrt(-4+0i) or (-4+0i)^0.5 (and get 0+2i in either case).
>
> cheers,
>
> Rolf Turner
>
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