In terms of n 1, 1, -1, -1, 1, 1, -1, -1,

  • Thread starter ziggie125
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  • #1
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Homework Statement



Put in general terms 1, 1, -1, -1, 1, 1, -1, -1, ...

Homework Equations





The Attempt at a Solution



obviously (-1)^n, alternates 1, -1, 1, -1...

I have no idea how to figure this out. I thought it might have a sin function in it possibly.
Thanks a lot for your help.
 

Answers and Replies

  • #2
jbunniii
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If you defined a function f(n) such that

f(0) = 0
f(1) = 0
f(2) = 1
f(3) = 1
f(4) = 2
f(5) = 2
...

then

[tex](-1)^{f(n)}[/tex]

would work, right? So try to find a simple formula for f(n).
 
  • #3
The [itex]i^{th}[/itex] term (starting with [itex]i=1[/itex]) could be [itex]\sqrt{2}sin\{(2i-1)\frac{\pi}{4}\}[/itex], but don't use that. You could probably use something similar to generate the [itex]f(i-1)[/itex] that jbunniii has suggested.

Of course, if the first number after the dots start is 42 you're in trouble.
 
  • #4
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Hey thx a lot for the help. Either method works fine, as long as you can figure out f(n) for the first one.
 

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