From: "Brian Schröder" <ruby@...>
Date: 2004-10-06T05:19:00+09:00
Subject: Re: A ruby course

Edgardo Hames wrote:
> 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
> 
I meant "bad for _my_ brain". Sorry if I have confused you. You were 
absolutely right, and I calculated the wrong thing.

Regards,

Brian

-- 
Brian Schr�der
http://ruby.brian-schroeder.de/