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Date: Thu, 19 Dec 2013 16:08:48 -0700
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To: Kris Craig <kris.craig@gmail.com>
Cc: "internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Re: power operator (again)
From: morrison.levi@gmail.com (Levi Morrison)

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On Thu, Dec 19, 2013 at 2:50 PM, Kris Craig <kris.craig@gmail.com> wrote:

> On Thu, Dec 19, 2013 at 4:33 AM, Daniel Lowrey <rdlowrey@gmail.com> wrote:
>
> > > Thanks for all your effort!  Unfortunately, since there's no option for
> > > negative numbers to intuitively square to positive outcomes, my vote is
> > > still No.  I understand and respect your reasoning even though I do not
> > > agree with it.
> >
> > To me this is not a question of "intuitive" vs. "unintuitive" ... -3^2 =
> -9
> > is how the preponderance of credible resources evaluate the expression.
> As
> > far as I can tell voting "no" on this basis is equivalent to me claiming
> > the earth is flat because it better fits my world-view.
>
>
> That's a faulty analogy.  In mathematics, the square of any number,
> positive or negative, yields a positive result.  Any scientific or graphing
> calculator will match that behavior.  I did sqr(-3) in the Windows
> Calculator just now and it outputted 9, not -9.
>

The problem here is that `pow(-3, 2)` is equivalent to the expression `(-3)
** 2`, not `-(3 **2)`. Said differently, `-3 ** 2` is equivalent to
`-pow(3,2)` and not `pow(-3,2)`.

Hopefully this helps.

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