- #1

- 467

- 7

1, 1, 2, 3, 5, 8, 13.....

if you do take f1*f3 - f2^2 you get

**1**

for the next in the series f2 you get f2*f4 - f3^2 you get

**-1**

and so on...

You keep getting 1, -1, 1, -1 for ever.... and i need to proove that. Could someone please do it, or has anyone got a link on the internet to it? I have been looking for hours :-(

[tex](F_n \cdot F_{n+2}) - (F_{n+1})^2 = (-1)^{n+1}[/tex]

Fn being a Fibonacci number

By convention F0 = 0, F1 = 1, so that F2 = 1.