------
## 最终结论
```python
import math

def calculate_radius(n):
    # Calculate the radius of the circumscribed circle of the regular 2n-gon
    radius = 1 / (2 * math.sin(math.pi / (2 * n)))
    return radius

def determine_side_length(n):
    radius = calculate_radius(n)
    side_length = 2 * radius
    return side_length

def read_input():
    import sys
    input = sys.stdin.read
    data = input().split()
    
    T = int(data[0])
    n_values = [int(data[i]) for i in range(1, T + 1)]
    
    return T, n_values

def compute_results(n_values):
    results = []
    for n in n_values:
        side_length = determine_side_length(n)
        results.append(side_length)
    return results

def output_results(results):
    for res in results:
        print(f"{res:.9f}")

# Main function to run the process
def main():
    T, n_values = read_input()
    results = compute_results(n_values)
    output_results(results)

# Uncomment this line if you want to run the code outside an environment that provides standard input redirection.
# main()
```