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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,522

That is not correct. With respect to t, 2pi*n is a constant, so it vanishes. You should have dt=dx.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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It does not vanish, multiplicative constants go to the front.

t = 2 n π x

dt/dx = 2 n π

dt = 2 n π dx

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**anonimnystefy****Real Member**- From: The Foundation
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You do not multiply x by it. You add it to x!

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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Oh brother, I am doing the wrong problem. You said t=x+n*2pi and I am doing t=x*n*2pi

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Yes. t=x+2pi*n.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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Okay thank you, I think I understand what he did there now.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**anonimnystefy****Real Member**- From: The Foundation
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Great! So, do you think you will be able to expand it to 1000 digits with that?

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**bobbym****Administrator**- From: Bumpkinland
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Hi;

Nope, objection 2 and 3 still apply.

Of course that result can be rigorously obtained, but who cares?

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**anonimnystefy****Real Member**- From: The Foundation
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Have you found any other ways?

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**bobbym****Administrator**- From: Bumpkinland
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Nothing that could exceed about 100 digits. I used my idea with a few more bells and whistles.

Of course that result can be rigorously obtained, but who cares?

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**anonimnystefy****Real Member**- From: The Foundation
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Have you had other propositions about finding more digits?

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**bobbym****Administrator**- From: Bumpkinland
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I am not following you. Propositions? Do you mean other ideas?

Of course that result can be rigorously obtained, but who cares?

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**anonimnystefy****Real Member**- From: The Foundation
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Have you had other propositions about finding more digits?

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**bobbym****Administrator**- From: Bumpkinland
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Other problems like this one?

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**anonimnystefy****Real Member**- From: The Foundation
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No. Did anyone tell you of another way to solve the integral problem?

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**bobbym****Administrator**- From: Bumpkinland
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I am afraid not.

Of course that result can be rigorously obtained, but who cares?

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Too bad. Be sure to tell me if you find something new.

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**bobbym****Administrator**- From: Bumpkinland
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If I were to find something new I would tell immediately but every new idea just evaporates.

Of course that result can be rigorously obtained, but who cares?

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**anonimnystefy****Real Member**- From: The Foundation
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Great then!

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**anonimnystefy****Real Member**- From: The Foundation
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bobbym wrote:

To start, although any CAS known will gag on this problem they are able to do pieces of so it is to our advantage to split the integral like this.

The first integral is not too difficult and any CAS can do it to 100 digits.

Hi bobbym

I wanted to ask you about this bit. How do I get Maxima to evaluate this?

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**bobbym****Administrator**- From: Bumpkinland
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What does maxima provide for numeric integration that is built in?

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**anonimnystefy****Real Member**- From: The Foundation
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I don't think there is anything built in.

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**bobbym****Administrator**- From: Bumpkinland
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There are numeric integration routines I think they are call quad_gags.

Also there is romberg and nint.

*Last edited by bobbym (2013-03-04 07:02:50)*

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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I tried loading nint, but it won't load!

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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Does this run?

```
(%i1) f(x) := (mode_declare (n, integer, x, float), n:n+1, exp(-x))$
(%i2) translate(f)$
Warning-> n is an undefined global variable.
(%i3) block ([rombergtol: 1.e-6, romberabs: 0.0], n:0, romberg (f, 0, 50));
(%o3) 1.000000000488271
(%i4) n;
(%o4) 257
```

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

**Online**