### Topic: Math help  (Read 1323 times)

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#### Corribus

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##### Math help
« on: November 01, 2018, 08:06:48 PM »
Can anyone figure out a simple expression for the following series of terms (n starting at 0 or 1)? I would like to express as a summation of terms.

x, 2-x, 2+x, 4-x, 4+x, 6-x, 6+x, .

? I can't think of one. Obviously I could break it into two summations but that becomes cumbersome.

Cyberbeer to whoever comes up with something.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

#### Corribus

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##### Re: Math help
« Reply #1 on: November 01, 2018, 11:14:21 PM »
I get to buy myself a beer. I had to use a few trigonometric functions. My expression is pretty ugly and could probably be simplified but I'm too tired.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

#### Enthalpy

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##### Re: Math help
« Reply #2 on: November 05, 2018, 02:22:14 PM »
Would this fit your needs?
n+0.5+(-1)n(x-0.5)
starts giving x for n=0.

(-1)n could be cos(n×π) if any better.