Math Is Fun Forum

I have found another way of finding the terms of a fibonacci numbers.   
                2          2
Fn   F   ) - (   F   )    ;where x+y=n and y=x-2.
         n-x         n-y
(or) Fn th term of the sequence is equal to the difference of squares of two fibonacci numbers F     and F
                                     n-x        n-y
where x+y=n and y=x-2

sum of first n terms of a fibonacci sequence is,
  Sn = ( F      )  - 1
            n+2