Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

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

 Messages: [ Previous | Next ]
 Clyde Greeno @ MALEI Posts: 220 Registered: 9/13/10
Re: Some important demonstrations on negative numbers
Posted: Nov 30, 2012 6:40 PM

On careful analysis, "i" is simply the unit along the *image axis*
(perpendicular to the *object axis*). It is only because of our interest in
the ("cyclonic") combinations, a*(c,d) + b*(-d,c) that the "multiplication"
of "complexes" ... (a,b)*(c,d) ... results in (0,1)*(0,1) = (-1,0). In the
non-symbolic form, "multiplication by i" simply amounts to counter-clockwise
rotation by 90-degrees.
- --------------------------------------------------
From: "Robert Hansen" <bob@rsccore.com>
Sent: Friday, November 30, 2012 4:42 PM
To: <math-teach@mathforum.org>
Cc: <math-teach@mathforum.org>
Subject: Re: Some important demonstrations on negative numbers

> Doubled.
>
> Bob Hansen
>
> On Nov 30, 2012, at 5:01 PM, Jonathan Crabtree
> <sendtojonathan@yahoo.com.au> wrote:
>

>>>
>>> On Nov 29, 2012, at 4:20 PM, Jonathan Crabtree

>> wrote:
>>>
>>>>> So what is i? I mean "i" as in the sqrt(-1), not
>>> the
>>>>> pronoun.
>>>>>
>>>>> Bob Hansen

>>>>
>>>> If you were to write the above using words only,

>>> without both abbreviations and symbols, what would
>>> you write?
>>>
>>>
>>> What number multiplied by itself once then added to
>>> one is zero?
>>>
>>> Bob Hansen

>>
>> OK thanks Bob. That was a great answer! Please keep playing along with
>> the next question. You might even get your son to answer with just a
>> single word...
>>
>> A number added to itself once, is said to have been WHAT?
>>
>> A number added to itself once, is said to have been...
>>
>> ==========
>> Thank you!

Date Subject Author
11/27/12 Peter Duveen
11/27/12 James Elander
11/27/12 Robert Hansen
11/27/12 Joe Niederberger
11/27/12 Clyde Greeno @ MALEI
11/27/12 Robert Hansen
11/27/12 Peter Duveen
11/28/12 Robert Hansen
11/27/12 Joe Niederberger
11/27/12 Robert Hansen
11/27/12 Joe Niederberger
11/28/12 Robert Hansen
11/27/12 Joe Niederberger
11/28/12 GS Chandy
11/28/12 GS Chandy
11/28/12 Robert Hansen
11/28/12 Peter Duveen
11/28/12 Robert Hansen
11/28/12 Robert Hansen
11/29/12 kirby urner
11/28/12 Peter Duveen
11/28/12 syeds
11/28/12 GS Chandy
11/28/12 Joe Niederberger
11/28/12 Paul A. Tanner III
11/28/12 Robert Hansen
11/29/12 kirby urner
11/28/12 Joe Niederberger
11/29/12 Paul A. Tanner III
11/28/12 Jonathan J. Crabtree
11/28/12 Joe Niederberger
11/29/12 Robert Hansen
11/28/12 Joe Niederberger
11/29/12 Peter Duveen
11/29/12 Peter Duveen
11/29/12 Joe Niederberger
11/30/12 Robert Hansen
11/29/12 Joe Niederberger
11/29/12 Joe Niederberger
11/29/12 Peter Duveen
11/29/12 Joe Niederberger
11/29/12 Jonathan J. Crabtree
11/29/12 Robert Hansen
11/29/12 Jonathan J. Crabtree
11/30/12 Robert Hansen
11/29/12 Joe Niederberger
11/30/12 Joe Niederberger
11/30/12 Robert Hansen
11/30/12 Joe Niederberger
11/30/12 Robert Hansen
11/30/12 Joe Niederberger
11/30/12 Robert Hansen
11/30/12 Joe Niederberger
11/30/12 Jonathan J. Crabtree
11/30/12 Robert Hansen
11/30/12 Clyde Greeno @ MALEI
11/30/12 Joe Niederberger
11/30/12 Clyde Greeno @ MALEI
11/30/12 Robert Hansen
12/1/12 Robert Hansen
11/30/12 Robert Hansen
11/30/12 Clyde Greeno
12/1/12 Robert Hansen
11/30/12 Jonathan J. Crabtree
12/1/12 Joe Niederberger
12/1/12 Robert Hansen
12/8/12 Clyde Greeno @ MALEI
12/1/12 Joe Niederberger
12/2/12 Jonathan J. Crabtree
12/2/12 Clyde Greeno @ MALEI
12/3/12 Robert Hansen