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Fibonacci sequence - calculating values

  1. Mar 27, 2008 #1
    a couple of days back I have learn about calculating fibonacci sequences but still I don;t quite uderstand the way it is calcilated, could you please give me some thoughts about it?

    Thank you
  2. jcsd
  3. Mar 28, 2008 #2
    it's easy
    [tex] F_{n+1} = F_{n} + F_{n-1} [/tex]

    So the next number in the series, [tex]F_{n+1}[/tex], is the sum of the previous two numbers

    We start with 1. 1 plus the previous number, 0, is 1. 1+0=1. Now our series is 1,1
    Now we take 1 and the number before it, 1 and add. 1+1=2. Now our series is 1,1,2
    Now we take 2 and the previous number, 1, and add. 2+1=3. Now our series is 1,1,2,3.
    Now take 3 and add the previous number, 2, and add. 3+2=5. 1,1,2,3,5
    5+3=8, 8+5=13, 13+8=21, ... Fib Series looks like 1,1,2,3,5,8,13,21,...

    got it?
    Last edited: Mar 28, 2008
  4. Mar 29, 2008 #3
    Thank you,
    my profesor teach me to use sqrt of 2 plus 5 all devide 2
    to calculate and i don't understand why. I am too scare to ask him again
  5. Mar 29, 2008 #4

    Gib Z

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    No, your teacher told you to use [itex]\frac{\sqrt{5}+1}{2}[/itex] to calculate Fibonnaci terms. That constant I just said is the golden ratio, commonly denoted by the greek letter "phi", [itex]\phi[/itex]. It is used in the closed form expression of the terms in the sequence. Don't be asked, you should ask him again.
  6. Mar 29, 2008 #5


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    … wikipedia … !

    Hi Mokae! :smile:

    If you don't understand something, wikipedia is usually a good place to look.

    For the siginificance of √5 in Fibonacci numbers, look at:

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