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Topic: Some important demonstrations on negative numbers
Replies: 70   Last Post: Dec 8, 2012 1:28 PM

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Peter Duveen

Posts: 163
From: New York
Registered: 4/11/12
Re: Some important demonstrations on negative numbers
Posted: Nov 29, 2012 1:31 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

To demonstrate that 1/-a = -(1/a):

(1/-a) x -a = 1 definition of 1/-a eq.1

- - (1/a) x a = -1 definition of 1/a

- -1 (1/a) x a = -1

(1/a) x -1 x a = -1

(1/a) x -a = -1

- -(1/a) x -a = 1 eq.2

>From eq. 1 and eq. 2:

- -(1/a) = (1/-a).

Perhaps a bit clumsy, but once demonstrated in its generality, the student no longer needs to wonder about this relationship when he sees a negative number in the denominator. As far as even clumsier analogies, that is fine to interpret the result as long as the result has been demonstrated clearly. Seems those who took geometry should easily assimilate such a demonstration (proof) .


Date Subject Author
11/27/12
Read Some important demonstrations on negative numbers
Peter Duveen
11/27/12
Read Re: Some important demonstrations on negative numbers
James Elander
11/27/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/27/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/27/12
Read Re: Some important demonstrations on negative numbers
Clyde Greeno @ MALEI
11/27/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/27/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/27/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/27/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/27/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/27/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/28/12
Read Re: Some important demonstrations on negative numbers
GS Chandy
11/28/12
Read Re: Some important demonstrations on negative numbers
GS Chandy
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/28/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/29/12
Read Re: Some important demonstrations on negative numbers
kirby urner
11/28/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/28/12
Read Re: Some important demonstrations on negative numbers
syeds
11/28/12
Read Re: Some important demonstrations on negative numbers
GS Chandy
11/28/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/28/12
Read Re: Some important demonstrations on negative numbers
Paul A. Tanner III
11/28/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/29/12
Read Re: Some important demonstrations on negative numbers
kirby urner
11/28/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Paul A. Tanner III
11/28/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
11/28/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/28/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/29/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/29/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/29/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Peter Duveen
11/29/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/29/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
11/29/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/29/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/29/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Clyde Greeno @ MALEI
11/30/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
11/30/12
Read Re: Some important demonstrations on negative numbers
Clyde Greeno @ MALEI
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
12/1/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Clyde Greeno
12/1/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
11/30/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
12/1/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
12/1/12
Read Re: Some important demonstrations on negative numbers
Robert Hansen
12/8/12
Read Re: Some important demonstrations on negative numbers > a MACS syllabus
Clyde Greeno @ MALEI
12/1/12
Read Re: Some important demonstrations on negative numbers
Joe Niederberger
12/2/12
Read Re: Some important demonstrations on negative numbers
Jonathan Crabtree
12/2/12
Read Re: Some important demonstrations on negative numbers > Wallis/Pycior
Clyde Greeno @ MALEI
12/3/12
Read Re: Some important demonstrations on negative numbers > Wallis/Pycior
Robert Hansen

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