from math import sqrt   # import de la fonction racine carree

def distance(point1, point2):
    """ Calcule et renvoie la distance entre deux points. """
    return sqrt((...)**2 + (...)**2)

def plus_courte_distance(tab, depart):
    """ Renvoie le point du tableau tab se trouvant a la plus
    courte distance du point depart."""
    point = tab[0]
    min_dist = ...
    for i in range (1, ...):
        if distance(tab[i], depart) ...:
            point = ...
            min_dist = ...
    return point