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**genericname****Member**- Registered: 2012-05-16
- Posts: 52

(2*(n/2)*lg(n/2)) + n

= (n*lg(n/2))+n

= n*(lg n - 1) + n

How does **(n*lg(n/2))+n** simplify to **n*(lg n - 1) + n**? What happened to the n/2 that was inside? It has been a while since I last worked with log.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi;

Is this the problem?

*Last edited by bobbym (2013-02-25 08:51:47)*

**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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**genericname****Member**- Registered: 2012-05-16
- Posts: 52

Yeah.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

I am getting:

*Last edited by bobbym (2013-02-25 10:10:52)*

**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
- Posts: 15,532

Hi genericname

lg(a/b)=lg(a)-lg(b) for any a and b for which the expression is defined.

So, lg(n/2)=lg(n)-lg(2)=lg(n)-1, assuming the logarithm is with base 2.

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

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Why would the log be to the base two?

**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
- Posts: 15,532

Because then the step makes sense. We will have have to wait for the OP's answer.

And besides, the use of n and lg reminds me of comp. analysis.

*Last edited by anonimnystefy (2013-02-25 14:42:40)*

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

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

A very good answer!

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

Combinatorics is Algebra and Algebra is Combinatorics.

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**genericname****Member**- Registered: 2012-05-16
- Posts: 52

Ah, thank you. It was base 2, sorry for the confusion.

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,532

No problem and you're welcome!

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

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