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#1 2012-10-23 01:21:33
- Mint
- Guest
Li(x)
What is li(x)?I know it is logarithmic integral function,but how do i find li(x),for instance,what will be li(5)?
#2 2012-10-23 02:08:45
- scientia
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#3 2012-10-23 02:40:17
- bobbym
- Administrator
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Re: Li(x)
Hi Mint;
Welcome to the forum.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#4 2012-10-23 05:55:38
- anonimnystefy
- Real Member
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Re: Li(x)
You can use the series given at http://en.wikipedia.org/wiki/Logarithmi … esentation
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
“A secret's worth depends on the people from whom it must be kept.” ― Carlos Ruiz Zafón
#6 2012-10-23 19:20:45
- bobbym
- Administrator
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Re: Li(x)
Depends on the arguments or how much accuracy you need. There are several ways for each.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#8 2012-10-23 19:31:47
- bobbym
- Administrator
Online
Re: Li(x)
Yes, but first I need that information from you.
1) Li(x), how big is x?
2)How many digits do you require because the answer is going to be in floating point.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#9 2012-10-23 20:07:52
- Mint
- Guest
Re: Li(x)
I just want to know how to find li(x),but you could show an example of your own.
#10 2012-10-23 20:12:41
- bobbym
- Administrator
Online
Re: Li(x)
Series are of different types. For small values of x we use Taylor series. For large values we use Asymptotic expansions and Series that are expanded around infinity.
1) You could try to evaluate the integral using Romberg or Gaussian integration.
2) You truncate the various series expansions producing smaller approximations.
3) You look up the values in tables.
I have used the second one to come up with an example:
When x>=500.
Read this:
http://numbers.computation.free.fr/Cons … rimes.html
now you will understand why there are only approximate answers.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.