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#1 2013-02-25 08:33:05
- genericname
- Member
- Registered: 2012-05-16
- Posts: 52
Log question
(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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#2 2013-02-25 08:50:27
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Log question
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.
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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#3 2013-02-25 08:58:06
- genericname
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- Registered: 2012-05-16
- Posts: 52
Re: Log question
Yeah.
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#4 2013-02-25 10:10:06
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Log question
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.
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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#5 2013-02-25 13:40:36
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Log question
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
The knowledge of some things as a function of age is a delta function.
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#6 2013-02-25 14:27:50
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Log question
Why would the log be to the base two?
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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#7 2013-02-25 14:41:10
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Log question
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
The knowledge of some things as a function of age is a delta function.
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#8 2013-02-25 16:31:10
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Log question
A very good answer!
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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#9 2013-02-26 03:44:16
- genericname
- Member
- Registered: 2012-05-16
- Posts: 52
Re: Log question
Ah, thank you. It was base 2, sorry for the confusion.
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#10 2013-02-26 06:19:58
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Log question
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
The knowledge of some things as a function of age is a delta function.
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