I struggle with order of convergence and functions, could you show me how I do that?

Problem 2 Assume we have a sequence of estimates {In } -> x* with true errors: Et,n = a* - In). What is the order of convergence of {On } for the following cases? (Note: we are interested in the order of convergence of the sequence, not O() convergence. ) a) Et,n+1 = Et,n b) Et,n+1 = Et,n c) Et,n = 2-n d) Et,n+1 = (Et,n)2 e) In+1 = g(n), for function g such that 0