Programme ecrit_2007_rattrapage_268_.py

# coding: latin-1
def racine_carree (k) :
    x0 = float (k)+1
    x  = float (k)
    while abs (x-x0) > 1e-10 :
        x0 = x
        x  = (k-x*x) / (2 * x) + x
    return x