Check if a number i is part of the Fibonacci sequence. Attempted to use the integer square root method so that large numbers could be arguments, but no dice, yet.

fibonacci

def is_fibonacci?(i)

x = 5 * i**2 + 4
m = x
p = x
  loop do
    r = (m + p.to_f / m).to_f / 2
    if m <= r
      break
    else
      m = r
    end
  end
y = 5 * i**2 - 4

n = y
o = y
  loop do
    q = (n + o.to_f / n).to_f / 2
    if n <= q
      break
    else
      n = q
    end
  end

m.denominator == 1 || n.denominator == 1

end