That&#x27;s given early in the article, but requires arbitrary precision arithmetic:<p>Another method is to find a closed form for the solution of the recurrence relation. This leads to the real-valued formula: Fib(n)=(ϕn+1−ψn+1)&#x2F;5‾√)
where ϕ=(1+5‾√)&#x2F;2 and ψ=(1−5‾√)&#x2F;2. The practical flaw in this method is that it requires arbitrary precision real-valued arithmetic, but it works for small n.