inverse square root python

1import math
2a = input("what do you wnat to square root")
3print(math.sqrt(a))

1import math
2print(math.sqrt(589485))

1import math
2answer = math.sqrt(16)

1import struct
2
3def isqrt(number):
4    threehalfs = 1.5
5    x2 = number * 0.5
6    y = number
7    
8    packed_y = struct.pack('f', y)       
9    i = struct.unpack('i', packed_y)[0]  # treat float's bytes as int 
10    i = 0x5f3759df - (i >> 1)            # arithmetic with magic number
11    packed_i = struct.pack('i', i)
12    y = struct.unpack('f', packed_i)[0]  # treat int's bytes as float
13    
14    y = y * (threehalfs - (x2 * y * y))  # Newton's method
15    return y