SOLUTION: I am doing work on the fabonacci sequence and one particular formula states http://upload.wikimedia.org/math/1/a/d/1ad54a3830f7ca7ad0c9295f115e5cd8.png However, when entering

Algebra ->  Square-cubic-other-roots -> SOLUTION: I am doing work on the fabonacci sequence and one particular formula states http://upload.wikimedia.org/math/1/a/d/1ad54a3830f7ca7ad0c9295f115e5cd8.png However, when entering       Log On


   

Question 62928: I am doing work on the fabonacci sequence and one particular formula states
http://upload.wikimedia.org/math/1/a/d/1ad54a3830f7ca7ad0c9295f115e5cd8.png
However, when entering in n, i just get back the number n I started with, not the n as in the actual number in the sequence. Help please
Answer by joyofmath(189) About Me  (Show Source):
You can put this solution on YOUR website!
Let me give you an example of the use of the formula and see if that helps.
The first 10 terms of the Fibonacci sequence are 1,1,2,3,5,8,13,21,34, and 55.
So, F%5B10%5D=55.
Let's see if we can get that with the formula F%5Bn%5D+=+%28p%5En-%281-p%29%5En%29%2Fsqrt%285%29 where p is phi, the Golden Ratio, which = %281%2Bsqrt%285%29%29%2F2 = approximately 1.618034 and n=10.
Also, it's useful to compute sqrt%285%29 = approximately 2.236068.
I got both the values above using a calculator.
Now, when n=10, F%5B10%5D+=+%281.618034%5E10-%281-1.618034%29%5E10%29%2F2.236068.
1.618034%5E10+=+122.991878.
%281-1.618034%29%5E10+=+.008136.
%281.618034%5E10-%281-1.618034%29%5E10%29+=+122.983742.
Finally, %281.618034%5E10-%281-1.618034%29%5E10%29%2F2.236068+=+55.00000.
So, we also get 55 by the formula.
Let me know if you still need help.