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## #51 2011-07-02 22:40:48

anonimnystefy
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### Re: Integration by Substitution

got that one.dunno what to do next.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #52 2011-07-02 22:52:35

bobbym

Online

### Re: Integration by Substitution

Hi;

gAr has a substitution that you will look at too.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #53 2011-07-02 23:04:43

anonimnystefy
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### Re: Integration by Substitution

hi

what substitution?

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #54 2011-07-02 23:06:56

bobbym

Online

### Re: Integration by Substitution

My way has led to a integration by parts which is tediuos but amounts to  plugging in to a formula.

If gAr has something else it may save you a whole lot of work. So let us wait for him.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #55 2011-07-02 23:10:10

anonimnystefy
Real Member

Offline

### Re: Integration by Substitution

ok,sure.just a question,is it possible to send private messages on this forum?

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #56 2011-07-02 23:11:26

bobbym

Online

### Re: Integration by Substitution

Yes, you must be a real member. That is awarded by MIF. Only he can do it.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #57 2011-07-02 23:12:53

anonimnystefy
Real Member

Offline

### Re: Integration by Substitution

yeah,how often does he come to the forum,because i don't see him active very much?

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #58 2011-07-02 23:15:37

bobbym

Online

### Re: Integration by Substitution

I see him every day.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #59 2011-07-02 23:17:24

anonimnystefy
Real Member

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### Re: Integration by Substitution

when?

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #60 2011-07-02 23:19:01

anonimnystefy
Real Member

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### Re: Integration by Substitution

me and MIF must be opposite time zones.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #61 2011-07-02 23:20:03

bobbym

Online

### Re: Integration by Substitution

I think so. Also he is usually busy working on the site.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #62 2011-07-02 23:21:36

anonimnystefy
Real Member

Offline

### Re: Integration by Substitution

let's stop this or otherwise there's a possibility that this topic turns into a chat topic.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #63 2011-07-02 23:24:37

bobbym

Online

### Re: Integration by Substitution

Brought to the front by moderator.

Hi

#### anonimnystefy wrote:

can anyone help me get:

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #64 2011-07-02 23:48:41

gAr
Star Member

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### Re: Integration by Substitution

Hi,

First lets derive a general formula for

First method is a more common one, integration by parts.
We'll need to use IBP twice, where we end up with the original integral on the RHS, and rearrange it.

Another method struck me:

Constant is not so cool to look at, I agree!

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #65 2011-07-02 23:55:53

anonimnystefy
Real Member

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### Re: Integration by Substitution

hi gAr

thanks.never thought of that.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #66 2011-07-03 00:12:57

gAr
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### Re: Integration by Substitution

Hi anonimnystefy,

You're welcome!

The constant is not "not cool" as I thought.
I forgot about substituting x back in the answer!

So what remains is:

Last edited by gAr (2011-07-03 00:13:25)

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #67 2011-07-18 02:57:17

gAr
Star Member

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### Re: Integration by Substitution

Hi,

A huge list of integrals, for fun and practice!

Skimming over it, I can say the problems have a quality!

That site is wonderful!
Don't miss the library: http://mpec.sc.mahidol.ac.th/library/oldbooks

Last edited by gAr (2011-07-18 03:21:07)

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #68 2011-08-02 20:55:16

gAr
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### Re: Integration by Substitution

Hi,

From AMM
11275

Find

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #69 2011-08-09 07:48:49

anonimnystefy
Real Member

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### Re: Integration by Substitution

here's one:

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #70 2011-08-09 16:33:00

gAr
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### Re: Integration by Substitution

Hi anonimnystefy,

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #71 2011-08-09 21:36:07

anonimnystefy
Real Member

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### Re: Integration by Substitution

hi gAr

thanks for looking for the problem.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #72 2011-08-09 22:13:23

gAr
Star Member

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### Re: Integration by Substitution

Hi anonimnystefy,

I'm not finished with it yet!
I posted it in haste because I had to go out for a while.
Now I'll take a longer look.

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #73 2011-08-09 22:23:15

anonimnystefy
Real Member

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### Re: Integration by Substitution

hi gAr

it's ok,take your time.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #74 2011-08-10 04:59:09

gAr
Star Member

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### Re: Integration by Substitution

Hi anonimnystefy,

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

## #75 2011-08-10 07:10:00

anonimnystefy
Real Member

Offline

### Re: Integration by Substitution

ok i will be waiting.

i don't have the solution.

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment