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Topic: Please remind me why -3^2 = -9
Replies: 26   Last Post: Nov 18, 2012 7:51 PM

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 Alain Schremmer Posts: 876 Registered: 10/10/05
Re: Please remind me why -3^2 = -9
Posted: Nov 18, 2012 7:51 PM

On Nov 18, 2012, at 10:57 AM, Matthews, George wrote:

> Not mentioned in previous responses to the question is the rationale
> for the conventional order of operations:
> Exponents (powers) before Products (or divisions) before Sums (or
> subtractions), in the absence of parentheses (grouping symbols),
> is convenience in writing polynomials.
> ax^p+bx^q+..., where x is a free variable, is much easier to read than
> (a(x^p))+(b(x^q))+...

I agree. The problem, though, is that the syntax for writing powers is
usually dealt with way before polynomials are dealt with. But, indeed,
there is really no reason for separating the two. After all, if we
evaluate a Laurent polynomial whose coefficients are single digits for
x <--- 10, then we get the decimal numbers with those digits.

> Those familiar with APL notation or Excel formulas are surely aware
> of these issues.
>
> That said, this forum should be open to any mathematical,
> pedagogical question without judgment about motives or intelligence.

Particularly when the question is very far from being trivial.

> Just my two cents.

Ditto

Regards
--schremmer
> ________________________________________
> From: owner-mathedcc@mathforum.org [owner-mathedcc@mathforum.org] on
> behalf of EddieC [info@kopworld.net]
> Sent: Sunday, November 18, 2012 6:28 AM
> To: mathedcc@mathforum.org
> Subject: Re: Please remind me why -3^2 = -9
>
> You're a teacher & you had to post this question?
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Date Subject Author
10/18/12 Phil Mahler
10/18/12 John Peterson
10/18/12 Guy Brandenburg
10/18/12 Wayne Mackey
10/18/12 Phil Mahler
10/18/12 RotmanJ
10/18/12 Paul Hertzel
10/18/12 Phil Mahler
10/18/12 Clyde Greeno
10/19/12 Clyde Greeno
10/19/12 Alain Schremmer
10/19/12 Wayne Mackey
10/19/12 Alain Schremmer
10/19/12 Clyde Greeno
10/19/12 Alain Schremmer
10/21/12 Wayne Mackey
11/14/12 Beth Hentges
11/15/12 Clyde Greeno
11/16/12 Alain Schremmer
10/18/12 Collinge, Peter (Mathematics)
10/18/12 Guy Brandenburg
10/18/12 Phil Mahler
10/18/12 Alain Schremmer
11/18/12 EddieC
11/18/12 Matthews, George
11/18/12 Phil Mahler
11/18/12 Alain Schremmer