Math Is Fun Forum
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#1 2012-07-07 01:12:13
Two Simple Questions
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#2 2012-07-07 01:14:47
- Bob
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- Registered: 2010-06-20
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Re: Two Simple Questions
2.
Multiply the two expressions and you'll get (abc)^3
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob 
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#3 2012-07-07 01:19:21
Re: Two Simple Questions
Wow! That's Nice and what about the first question
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#4 2012-07-07 01:27:30
- Bob
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- Registered: 2010-06-20
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Re: Two Simple Questions
I think the following works:
EDIT I'm having second thoughts about this ............
I, now, don't think it does. see post #7 for corrected version
I have removed this version because it had an error.
I had forgotten that if you square both sides of an inequality the sign reverses when both quantities are negative.
eg. -4 < -3 but 16 > 9
I have taken care to avoid this in post #7.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#5 2012-07-07 01:35:49
- Bob
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- Registered: 2010-06-20
- Posts: 10,582
Re: Two Simple Questions
No. It doesn't work because subtracting causes negative values and the > < signs reverse at the next squaring.
I'll try to improve this.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#6 2012-07-07 01:39:29
Re: Two Simple Questions
Hmm..
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#7 2012-07-07 01:54:09
- Bob
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- Registered: 2010-06-20
- Posts: 10,582
Re: Two Simple Questions
Ok. This version is more carefully done.
I'm going to make up two more useful signs ..... £ is either > or < and $ is the opposite sign ( < or >)
To start with I'll use £ between the two expressions.
Whenever I want to x by -1 I'll switch to the other sign.
I'll aim for an expression I can evaluate by hand.
Then i'll know what sign to insert and so i'll be able to work back as before.
R17 - R12 £ R11 - R6
squaring will not alter this sign as both expressions are obviously positive.
17 + 12 - 2.R17.R12 £ 11 + 6 - 2.R11.R6
subtract 17 will not change the sign
12 - 2.R17.R12 £ -2.R11.R6
divide by 2 will not affect the sign
6 - R17.R12 £ R11.R6
add R17.R12 to both sides (will not change the sign)
6 £ R17.R12 - R11.R6
note: the RHS is positive so squaring will not affect the sign
36 £ 204 + 66 - 2.R17.R12.R11.R6
-234 £ - 2.R17.R12.R11.R6
times by minus 1. sign changes
234 $ 2.R17.R12.R11.R6
divide by 2
117 $ R17.R12.R11.R6
evaluate long hand
13689 $ 13464
this means that $ = >
so £ means the opposite <
so R17 - R12 < R11 - R6
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#8 2012-07-07 02:04:57
Re: Two Simple Questions
Thank You
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#9 2012-07-07 03:32:26
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Two Simple Questions
Hi agnishom;
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#10 2012-07-07 14:00:37
Re: Two Simple Questions
That is great
Do you mean him: http://www.mathisfunforum.com/profile.php?id=13523 ?
Last edited by Agnishom (2012-07-07 14:28:02)
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#11 2012-07-07 14:38:29
Re: Two Simple Questions
Another Question
If
then what is the value of ?
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#12 2012-07-07 14:44:44
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Two Simple Questions
Hi Agnishom
I think the answer is 1. Start by expressing the terms in each brqcket in terms of a,b and c.
Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.
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