# 11.934321459

Discussion in 'Physics & Math' started by LionHearted, May 15, 2003.

1. ### LionHeartedRegistered Senior Member

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105
Is there anything significant about this number? I noticed that the function f(x) = -x(x+pi)(x-pi)/11.934321459 is the same as f(x) = sin x on the interval (-pi, pi). Is there any good reason for that number to be the denominator?

3. ### ryansCome to see me about a dog heyRegistered Senior Member

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995
Its not the same, it just looks the same. It looks like a taylor series expansion for sin(x) up to third order.

5. ### oxymoronRegistered Senior Member

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454
Special Numbers

142857

Time's a tickin'

7. ### letheRegistered Senior Member

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2,009
Re: Special Numbers

repeating digits of 1/7

8. ### James RJust this guy, you know?Staff Member

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37,189
...which also means it's a cyclic number.

9. ### LionHeartedRegistered Senior Member

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105
Re: Re: Special Numbers

What do you mean by repeating digits of 1/7?

10. ### everneoRe-searcherRegistered Senior Member

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Re: Re: Re: Special Numbers

1/7 = .142857142857142857...

Last edited: May 15, 2003

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-AntonK

12. ### letheRegistered Senior Member

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2,009
what s a cyclic number?

13. ### oxymoronRegistered Senior Member

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454
Cyclic numbers are special numbers that when multiplied by an integer produces a number with the same digits but in a different order.

142857 * 2 = 285714

Sum of 142857 = 27

Sum of 142857 * 8 = 27 as well.

However 142857 * 7 = 999999, which means that a cyclic number multiplied by it's fraction-generator gives a string of 9's.

I think these numbers are really cool. Apparently Lewis Carroll worked 142857 one out many, many years ago!

Here is another cyclic number:

588235294117647

14. ### James RJust this guy, you know?Staff Member

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37,189
142857 &times; 2 = 285714
142857 &times; 3 = 428571
142857 &times; 4 = 571428
142857 &times; 5 = 714285
142857 &times; 6 = 857142

Multiples produce the same digits in a different order.

<a href="http://mathworld.wolfram.com/CyclicNumber.html" target="_blank">Cyclic Numbers</a>

15. ### LogicalAtheistGuest

Neat. Math without application is such a lonely thing is it not?

It's like a play that's never acted out, A song that's never played, A dance that's never danced!

16. ### ryansCome to see me about a dog heyRegistered Senior Member

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It's the best kind of math. All arguements are based on a few simple axioms which must be adhered to, other than that you can do anything you want. Personally I think theoretical physics is much more difficult to grasp than advanced mathemetics. Mathematics is bound by our logic, physics is bound by the logic of mother nature, who seems to be continually changing her mind.

17. ### CanuteRegistered Senior Member

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1,923
Didn't know about cyclic numbers. They have curious properties that look algorthymically useful. Have we found nature making use of them? (as with Fibonnachi series etc).

18. ### ryansCome to see me about a dog heyRegistered Senior Member

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995
Don't know about cyclic numbers, but cyclic permutations have definately been used to describe nature.