#The solution in Python 3 is as follows:
for _ in range(int(input())): print ('%.6f' % (1 - (2**0.5/3)/(int(input())**0.5)))
#Keep visiting for more solutions of SPOJ problems in Python 3.Thank you!!!
for _ in range(int(input())): print ('%.6f' % (1 - (2**0.5/3)/(int(input())**0.5)))
#Keep visiting for more solutions of SPOJ problems in Python 3.Thank you!!!