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

 Messages: [ Previous | Next ]
 Clyde Greeno Posts: 68 Registered: 5/21/10
Re: Please remind me why -3^2 = -9
Posted: Oct 19, 2012 12:22 PM

A Mackey-prompted extension:

"Below, insert parens to show two reasonable interpretations of '-x^y' ...
and circle the one that is most commonly used in mathematical literature:
-x^y or -x^y "
... then illustrate the difference, by evaluating both formulas, by choosing
a value for x, and a value for y, and using those values in each of your two
parenthesized formulas. Which of those values is displayed by your
calculator ... with and without your parens "

Cordially,
Clyde

- --------------------------------------------------
From: "Wayne Ford Mackey" <wmackey@uark.edu>
Sent: Friday, October 19, 2012 9:50 AM
To: "Alain Schremmer" <schremmer.alain@gmail.com>; "Clyde Greeno"
<greeno@malei.org>
Cc: "Philip Mahler" <mahlerp@middlesex.mass.edu>; "mathedcc"
<mathedcc@mathforum.org>
Subject: RE: Please remind me why -3^2 = -9

> What if a student has to replace x by 3 in the expression - x^2?
> Shouldn't he or she know the result?
>
> wayne
>
> ________________________________________
> From: owner-mathedcc@mathforum.org [owner-mathedcc@mathforum.org] on
> behalf of Alain Schremmer [schremmer.alain@gmail.com]
> Sent: Friday, October 19, 2012 7:19 AM
> To: Clyde Greeno
> Cc: Philip Mahler; mathedcc
> Subject: Re: Please remind me why -3^2 = -9
>
> On Oct 19, 2012, at 12:48 AM, Clyde Greeno wrote:
>

>> In this case, the challenge to the student might be:
>> "Below, insert parens to show two reasonable interpretations of
>> '-3^2' ... and circle the one that is most commonly used in
>> mathematical literature:
>> -3^2 or -3^2 "

>
> Very nice!!!
> Best regards
> --schremmer
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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