|
|
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!
|
|
