Math Is Fun Forum
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#26 2014-11-08 17:47:48
Re: Is there such a function?
Isn't sin(x) such a function?
'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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#27 2014-11-08 21:13:59
- anonimnystefy
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- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
It is not. It has countably many such points.
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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#28 2014-11-09 00:23:19
Re: Is there such a function?
How about the Weierstrass function?
Suppose It was countable. Then I could create a bijection between the peaks and N. Now, pick the peaks numbered 1 and 2, there are still infinite peaks unnumbered between them. So, the bijection does not exist.
Last edited by Agnishom (2014-11-09 00:24:10)
'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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#29 2014-11-09 01:42:16
- ShivamS
- Member
- Registered: 2011-02-07
- Posts: 3,648
Re: Is there such a function?
A variant on the bump function?
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#30 2014-11-09 03:01:45
Re: Is there such a function?
What would that be?
'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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#31 2014-11-09 04:46:38
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
Actually, the answer is that it does not exist, but I don't know how to prove that.
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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#32 2014-11-09 04:50:21
Re: Is there such a function?
Why doesn't Weierstrass function satisfy the condition?
'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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#33 2014-11-09 05:16:18
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
I don't think there are uncountably many peaks, but I'm not sure.
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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#34 2014-11-10 04:10:56
Re: Is there such a function?
What is the standard way to show something is uncountable?
'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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#35 2014-11-10 08:18:20
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
I asked a professor today about this problem and also found out the answer to your question.
It's needed to be shown that each of those extreme points can be isolated inside an interval so that no two intervals intersect.
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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#36 2014-11-10 17:57:09
Re: Is there such a function?
Could you do it? Did the professor point out any other such function?
'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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#37 2014-11-10 22:17:29
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
Well, I found this: http://books.google.rs/books?id=Cqk5AAA … um&f=false
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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#38 2014-11-10 23:39:48
Re: Is there such a function?
That page is in russian, so ...
'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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#39 2014-11-11 02:04:02
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
It's more likely in Serbian, but that's not important. The book is in English.
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.
Offline
#40 2014-11-11 02:10:31
Re: Is there such a function?
How does the countablity of Q x Q help?
'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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#41 2014-11-11 02:33:20
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Is there such a function?
Well, each of those intervals has rational endpoints, so there are certainly countably many.
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.
Offline
#42 2014-11-11 03:24:27
Re: Is there such a function?
I do not really understand the proof but it sounds depressing. 
A new question I think the Amazon Customer Care should be asked.
Last edited by Agnishom (2014-11-11 03:27:48)
'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.
Offline
#43 2014-11-11 03:51:25
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Is there such a function?
I have received a complaint from them about you.
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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#44 2014-11-11 04:29:12
Re: Is there such a function?
What is the atatement of the complaint?
'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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#45 2014-11-11 04:32:44
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Is there such a function?
They said some person or possibly several persons were asking their overworked and underpaid customer service agents questions they could not understand. They wanted to know if that was a portrait of you.
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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#46 2014-11-11 04:40:27
Re: Is there such a function?
Portrait? Which is the portrait?
'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.
Offline
#47 2014-11-11 04:41:06
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Is there such a function?
Post #46, look on the left.
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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#48 2014-11-11 04:43:00
Re: Is there such a function?
Do you think I should get a job at Amazon Customer Care after I complete my graduation?
'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.
Offline
#49 2014-11-11 04:44:39
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Is there such a function?
You might try but I would leave out the part about calling them up.
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.
Offline
#50 2014-11-11 04:50:44
Re: Is there such a function?
Underpayment is a serious issue.
'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.
Offline