t = read_line.to_i
b = 100
len = 1.0 / Math::E / (Math::PI ** 2) / b
t.times do
  n = read_line.to_i
  sum = Math::E
  1.upto(b - 1) do |i|
    sum += Math.exp(Math.cos(len * i / n)) * 2.0
  end
  sum += Math.exp(Math.cos(len * b / n))
  sum *= len / 2
  printf("%.10f\n", sum)
end