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Topic: Help with creating a function
Replies: 12   Last Post: Nov 19, 2013 3:48 AM

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Posts: 12,067
Registered: 7/15/05
Re: Help with creating a function
Posted: Nov 18, 2013 7:12 AM
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quasi wrote:
>quasi wrote:
>>Robert Crandal wrote:
>>>Suppose I have the following X-Y data set:
>>>X Y
>>>-- --
>>>0 1
>>>1 1
>>>2 2
>>>3 3
>>>. .
>>>. .
>>>N N
>>>Can this be represented with a math function?
>>>(Only consider positive integers >= 0)

>>It's already a function since for each x in the domain, there
>>is a unique y.
>>Presumably you want a "formula".
>>The function f defined on the set of nonnegative integers
>>by the formula
>> f(x) = ((x-1)*(((2*x-1)/abs(2*x-1))+1)/2)+1
>>is not pretty but it works.

>Here's a simple one based on the floor function.
> f(x) = x + floor(1/(x+1))

This one uses factorials.

f(x) = x + (1/2)*(1 - (-1)^(x+1)!)


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