From: Edgardo Hames <ehames@...>
Date: 2004-10-06T04:58:20+09:00
Subject: Re: A ruby course

On Wed, 6 Oct 2004 04:36:23 +0900, Brian Schr�der
<ruby@brian-schroeder.de> wrote:
> Edgardo Hames wrote:
> >>>
> >>>You could extend Integer with a fibonacci method, so that you can
> >>>write something like:
> >>>
> >>>puts 0.fibonacci       > 0
> >>>puts 1.fibonacci       > 1
> >>>puts 5.fibonacci       > 5
> >>
> >>Should be 12, shouldn't it?
> >
> >
> > 0.fib  > 0
> > 1.fib  > 1
> > 2.fib  > 1
> > 3.fib  > 2
> > 4.fib  > 3
> > 5.fib  > 5
> >
> 
> Oh, 12 was the sum of the fibonaccy numbers up to 5. Too much thinking
> is bad for your brain.
> 

What are you talking about? As far as I know the fibonacci series is defined as

fib n = fib (n-1) + fib (n-2)

Then,
fib 5 = 
= fib 4 + fib 3
= (fib 3 + fib 2) + (fib 2  + fib 1)
= ((fib 2 + fib 1) + (fib 1 + fib 0)) + (fib 1 + fib 0) + (1+0)
= ((fib 1 + fib 0) + (1+ 0))+ (1+0) + (1+0) + (1+ 0)
= 1+1+1+1+1
= 5

You might cosider taking a look at 
http://mathworld.wolfram.com/FibonacciNumber.html
It defines fib 0 = 0,  but either way, 12 doesn't belong to the series.

Regards,
Ed

-- 
" Don't relax!  It's only your tension that's holding you together."