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Author Topic: 1 = -1?  (Read 11553 times)

Offline myriam

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1 = -1?
« Reply #25 on: 24/05/2010 22:05:37 »
hello

(x)E(a*b)= ((x)E(a))E(b) if and only if x>0

:)
 

Offline JP

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« Reply #26 on: 25/05/2010 02:25:15 »
What is E?  What do all the extra parentheses mean?
 

Offline imatfaal

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« Reply #27 on: 25/05/2010 14:05:18 »
hello
(x)E(a*b)= ((x)E(a))E(b) if and only if x>0
:)

Do you mean this


let x=-4, a=2, b=3

i.  (-4)^(2*3)    = 4096
ii. (-4)^2 = 16
             16^3 = 4096

A. I fail to see how this connects to initial problem (per TommyA)
B. Unless I am untangling your brackets incorrectly I don't agree with your statement
 

Offline imatfaal

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« Reply #28 on: 25/05/2010 17:19:22 »
Tommy - E was in the past (I think) used to mean Exponential: similar to using x^2 to mean x squared we could write xE2. But I am by no means sure.

You're right, the initial problem was a "proof" that 1= -1.  And I don't see how the equation that Myriam gave (which I cannot interpret sensibly) has anything to do with it.
 

Offline Geezer

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1 = -1?
« Reply #29 on: 26/05/2010 03:09:20 »

I looked at a post JP asked what E was and I did not see a response.
And I see JP has allot on the ball from other prior posts
  

I think JP is too young to remember the Exponent button on calculators. I'm pretty sure he's never seen a slide rule either ;D I've still got mine.

It's a bit scary to realize that I was raised in a different era, although, that would probably explain why my knees tend to seize up.
 

Offline JP

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« Reply #30 on: 26/05/2010 04:08:22 »
I think I saw one of those calculators in a museum once.  And slide rule?  Does that have something to do with playground behavior?

(The programs I use to do mathematics these days use (x)E(y)=xey rather than xy). 
 

Offline Geezer

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« Reply #31 on: 26/05/2010 06:55:07 »
Yea and a book of log base 10
 

Ah yes! The dreaded log tables. If I can find mine, I'll post a photo for posterity.
 

Offline imatfaal

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« Reply #32 on: 26/05/2010 19:19:34 »
Lovely stuff Tommy - I have an old cambidge scientific somewhere (led screen); one of the first pocket calculators easily available in UK.  I think it was bought for elder brothers doing o'level maths in 74 - maybe for a'level.
to my shame I still don't know how to use a slide rule
 

Offline Geezer

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« Reply #33 on: 27/05/2010 00:22:38 »
Alas, my Sinclair Scientific has long since bit the dust.
 

Offline RD

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« Reply #34 on: 27/05/2010 02:11:28 »
« Last Edit: 27/05/2010 02:36:56 by RD »
 

Offline RD

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« Reply #35 on: 27/05/2010 03:00:56 »
Imagine having this calculator for 19 years, then finding it in a lost corner of the house, with no an instructional guidebook. Hair is getting thin from constant head and scalp abuse.
My wife says, sure you save everything else.
It will Show in the most unlikely place.

Like the internet ...


http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000050415.pdf

« Last Edit: 27/05/2010 04:22:08 by RD »
 

Offline imatfaal

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« Reply #36 on: 27/05/2010 12:36:50 »

o'level maths in 74 - maybe for a'level.
Terminology what are these related to in layman's terms they are really new to me.. does the prefix (AZ) apply?
Is it like the state here call it EEG... (math 101) etc... being the most elementry to the Diff EQ ?
 

Qualifications which are almost as outdated now as the sliderules.  O'levels (ordinary level) were taken at age 16 - and one would take a whole bunch ranging from physics to music, french to woodwork, english lit to philosphy (I ended up with 13); and were used, amongst other things, to filter access to last two years of school education (what we called the sixth form).  A'levels (advanced level) were much more specialised and taken at 18, one would generally take three or four; these were used to filter entrance to university.  Graded between A-E (and U for terrible), A-C were passes at O'level, A-E at A'level.  other wierder ones were AO (alternative ordinary - often maths) and S (special).   Its all changed now.  Someone with kids of right age can explain further   
 

Offline BenV

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« Reply #37 on: 28/05/2010 17:28:57 »

o'level maths in 74 - maybe for a'level.
Terminology what are these related to in layman's terms they are really new to me.. does the prefix (AZ) apply?
Is it like the state here call it EEG... (math 101) etc... being the most elementry to the Diff EQ ?
 

Qualifications which are almost as outdated now as the sliderules.  O'levels (ordinary level) were taken at age 16 - and one would take a whole bunch ranging from physics to music, french to woodwork, english lit to philosphy (I ended up with 13); and were used, amongst other things, to filter access to last two years of school education (what we called the sixth form).  A'levels (advanced level) were much more specialised and taken at 18, one would generally take three or four; these were used to filter entrance to university.  Graded between A-E (and U for terrible), A-C were passes at O'level, A-E at A'level.  other wierder ones were AO (alternative ordinary - often maths) and S (special).   Its all changed now.  Someone with kids of right age can explain further  

I'll take that challenge.

This should be relatively up to date, but for the UK only...

At 16, you take GCSE exams (general certificate of secondary education) - roughly equivalent to O levels.

A Levels are now split, to encourage diversity - most 16+ students now take 6 AS levels for one year, then can chose to 'enhance' some of them up to full A levels by studying a subset of those subjects for an extra year.  Some (but very few) UK schools offer the International Baccalaureate - an alternative to A levels.

There are other options which are largely less academic and more practical - such as City & Guilds qualifications or GNVQs (general national vocational qualifications).
 

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1 = -1?
« Reply #37 on: 28/05/2010 17:28:57 »

 

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