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**zetafunc.****Guest**

If only I knew this before I did this problem! These things really do simplify combinatorics problems...

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Probability problems too:

This is probability generating polynomial for throwing a die 5 times.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**zetafunc.****Guest**

Yes, I have seen those ones. Unfortunately with the probability questions they ask, I can never seem to find the right GF so I have to use other methods.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

That can be tough finding the right one sometimes you have to construct it.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**zetafunc.****Guest**

If only every problem had a GF...

...does every problem have a GF?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

I asked that question to a bunch of mathematicians, I got no answer.

I would say it is very easy to see that there is a generating polynomial but will there always be a generating function?

Look at this series:

It is unlikely that there is a gf for those coefficients.

But would that come up in a combinatorics problem? Probably not. So the question,"does every combinatoric problem have a gf?" I can not answer definitely but I think yes!

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

**Online**

**zetafunc.****Guest**

We almost got to do some combinatorics in chemistry today (he was explaining entropy). Unfortunately we never did any maths, just listed some possibilities.

Greatest part was when he asked how many ways there were to arrange 4 objects, nobody knew. The teacher listed them all and concluded from his list that the answer must be 22.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Technically, that is not combinatorics what he did. Someone described combinatorics as the art of counting without actually counting.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

I read that somewhere too. It would be nice if they knew about it though, then he wouldn't have to count. There is a module we have to do called 'combinatorial chemistry'. Containing no combinatorics...

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

With me it was just the opposite.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

What do you mean?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

When they started getting into some math for chemistry I freaked out. It destroyed my future.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

What, why?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Hi;

Sorry, a bunch of morons are calling me about a census. I have been ducking them but not any longer. I will have to answer their question. See you after I am done.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

Okay, see you later.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Sorry, they wanted to know about grocery shopping in my area.

The first time I saw a real math problem I was unable to understand it. I had to drop chemistry which was what I wanted to do for life.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

What maths problem?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

They were K ionization, K equilibrium and Constant solubility products. They were not the problem, the numbers were!

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

Interesting, I am studying those right now...

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

It was the first time I saw scientific notation. Thanks to my math classes I thought all numbers were like 1,2,3,4, 1/2, 1/4, √2, π. When I saw

I could not deal with it or understand it.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

They didn't have calculators in your day?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Nope, I taught myself how to use a slide rule. The shock of seeing numbers like that and having to work with equations that had them was too much. The chem teachers tried to teach us but those stupid math classes never prepared us to work with numbers, real numbers.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

Chem teachers could do arithmetic in those days? The modern chem teacher says that 1/0 = 1, pi is approximately 3, and that you are a genius if you can do 4*3*2*1 without a calculator.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,998

Back then my chem teachers could calculate much better than a math teacher could. This was not unusual, the greatest living numerical analyst is Forman S. Acton and he is a chemist.

**In mathematics, you don't understand things. You just get used to them.**

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**zetafunc.****Guest**

I haven't heard of him, I was surprised he was born in 1920, that is quite old...