Let (n) be a sequence in M and let a M and k 0. Suppose that d(a, xn+1) |k|d(a,xn) for all n E N. Let qn = g(n) be a number such that d(a, xn+1) an d(a, x) for all n E N. Give qn and the range R of values of k for which the sequence (rn) is convergent.