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#1 2014-05-09 22:36:07

caspertts
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Registered: 2014-05-09
Posts: 3

help me! Q=D={x|x is an integer such that x^2=2)

first of all, hello I'm new here and I'm not good in math so I decided to join this forum,hope we can help each other!

this is the question that I don't know the answer

D={x|x is an integer such that x^2=2)
list the elements of D


if I √2,  I will not get the value of x in integer isn't?

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#2 2014-05-09 22:48:20

zetafunc.
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Re: help me! Q=D={x|x is an integer such that x^2=2)

caspertts wrote:

if I √2,  I will not get the value of x in integer isn't?

So what can you say about the set, D?

#3 2014-05-09 22:51:59

caspertts
Member
Registered: 2014-05-09
Posts: 3

Re: help me! Q=D={x|x is an integer such that x^2=2)

zetafunc. wrote:
caspertts wrote:

if I √2,  I will not get the value of x in integer isn't?

So what can you say about the set, D?

containt no element?

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#4 2014-05-09 22:53:54

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,764
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Re: help me! Q=D={x|x is an integer such that x^2=2)

The set is

Welcome to the forum;

What is your favorite color?


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#5 2014-05-09 23:02:54

caspertts
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Registered: 2014-05-09
Posts: 3

Re: help me! Q=D={x|x is an integer such that x^2=2)

Agnishom wrote:

The set is

Welcome to the forum;

What is your favorite color?

thanks!my next question,if

A={1}
D={∅}

then A∩D?


sorry for asking simple question like this , favorite color?blue!

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#6 2014-05-10 00:27:47

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

hi caspertts

Welcome to the forum.

A intersection 'phi' is everything in both.  But they haven't got any common elements so it's the empty set again.

Have a look here:

http://www.mathsisfun.com/sets/sets-introduction.html

If that's too simple then use the search with the word 'sets' to find lots more.

Bob

Strictly speaking the empty set is { } not {phi}.  There is a difference which I'll explain if you want.

Last edited by bob bundy (2014-05-10 00:30:59)


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

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#7 2014-05-10 00:37:16

Agnishom
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From: Riemann Sphere
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Re: help me! Q=D={x|x is an integer such that x^2=2)

sorry for asking simple question like this

Do not be sorry. All questions are worthy questions.

Yoda wrote:

A fool, no questioner is. By asking, wiser he becomes.


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#8 2014-05-10 01:07:01

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

All questions are worthy questions.

I agree with your sentiment but what about:

Is it FALSE to say this question is worthy?

smile

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

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#9 2014-05-10 01:18:56

Agnishom
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From: Riemann Sphere
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Re: help me! Q=D={x|x is an integer such that x^2=2)

Axiom: All questions are worthy.

Question: Is it FALSE to say this question is worthy?

Answer: No. [by axiom]

Which part of the axiom is contradicted?


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#10 2014-05-10 05:40:00

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

I concede your point.  smile

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

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#11 2014-05-10 05:44:37

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,764
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Re: help me! Q=D={x|x is an integer such that x^2=2)

cool yay!


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#12 2014-05-10 06:11:02

bob bundy
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Registered: 2010-06-20
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Re: help me! Q=D={x|x is an integer such that x^2=2)

Don't get too happy.  I may yet find a sentence that does what I was intending.  smile

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

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#13 2014-05-10 12:25:45

Agnishom
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From: Riemann Sphere
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Posts: 21,764
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Re: help me! Q=D={x|x is an integer such that x^2=2)

Not necessarily.

There are undoubtedly properties about questions which you cannot prove false.Example: All questions end with a question mark


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#14 2014-05-10 13:37:16

ShivamS
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Registered: 2011-02-07
Posts: 3,646

Re: help me! Q=D={x|x is an integer such that x^2=2)

bob bundy wrote:

Don't get too happy.  I may yet find a sentence that does what I was intending.  smile

Bob

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#15 2014-05-10 20:13:51

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

hi Agnishom,

After much further thought, I find I am able to find any inconsistency or logical flaw in your theory.  I therefore hold it to be a good theory.  smile

Do you want to name it?  How about "Agnishom's First Worthiness Theory"?

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

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#16 2014-05-14 13:17:28

ShivamS
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Registered: 2011-02-07
Posts: 3,646

Re: help me! Q=D={x|x is an integer such that x^2=2)

bob bundy wrote:

I find I am able to find any inconsistency or logical flaw in your theory.

Your post does not make sense eek

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#17 2014-05-14 19:14:07

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

O yes.  Meant to be 'unable to find'.  Whoops.

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

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#18 2014-05-14 19:28:26

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,764
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Re: help me! Q=D={x|x is an integer such that x^2=2)

Can we name it 'Fundamental Theorem of Worth'?


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#19 2014-05-15 10:15:47

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

Fundamental Theorem of Worth it is then.  Congratulations.  smile

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

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#20 2014-05-15 13:01:47

ShivamS
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Registered: 2011-02-07
Posts: 3,646

Re: help me! Q=D={x|x is an integer such that x^2=2)

Prove the theorem. I thought it was an axiom.

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#21 2014-05-20 00:29:13

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

ShivamS wrote:

Prove the theorem. I thought it was an axiom.

You are right.  smile  Let's amend it to: "Fundamental Theory of Worth."

Is that OK ?

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

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#22 2014-05-20 00:33:58

ShivamS
Member
Registered: 2011-02-07
Posts: 3,646

Re: help me! Q=D={x|x is an integer such that x^2=2)

It has not been proven. It must be an axiom or a hypothesis.

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#23 2014-05-20 01:05:19

bob bundy
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Registered: 2010-06-20
Posts: 7,071

Re: help me! Q=D={x|x is an integer such that x^2=2)

We have an axiom:

Agnishom wrote:

Axiom: All questions are worthy.

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

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#24 2014-05-20 01:06:08

ShivamS
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Registered: 2011-02-07
Posts: 3,646

Re: help me! Q=D={x|x is an integer such that x^2=2)

A theory is usually supported by some empirical evidence.

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#25 2014-05-20 02:00:45

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 15,937

Re: help me! Q=D={x|x is an integer such that x^2=2)

Not really. Number theory, for example.


“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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