def iloraz(tab, n, f):
    pom = []
    for i in range(n):
        pom.append(f(tab[i]))
    for i in range(n):
        j = n-1
        while j > i:
            pom[j] = (pom[j] - pom[j-1])/(tab[j] - tab[j-i-1])
            j -= 1
    return pom[n-1]