Fibonacci Calculator

Calculate values related to the Fibonacci sequence using Binet's formula approximation.

Fib N

55

Golden Ratio1.61803399
Fib N Minus 134
Ratio1.61764706

Fibonacci Sequence

Definition

F(0) = 0, F(1) = 1, F(n) = F(n-1) + F(n-2)

Sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

Binet's Formula

F(n) = (phi^n - psi^n) / sqrt(5)

where phi = (1 + sqrt(5))/2 (golden ratio) and psi = (1 - sqrt(5))/2.

For large n, psi^n approaches 0, so F(n) ≈ phi^n / sqrt(5).

Golden Ratio

As n grows, F(n)/F(n-1) approaches the golden ratio phi ≈ 1.6180339887.

Example Calculation

Find the 10th Fibonacci number.

  1. 01F(10) = phi^10 / √5
  2. 02= 1.61803^10 / 2.23607
  3. 03≈ 122.992 / 2.236
  4. 04≈ 55
  5. 05Sequence up to F(10): 0,1,1,2,3,5,8,13,21,34,55

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