3.15 Under the compound-interest accumulation function, i.e., a(t) = (1 + i), show that (a) ip = i, for all t> 0. (b) The accumulation function for payments due at time t, assuming the payments earn the forward rates of interest, is af(T) = (1 + i)" (c) it. T = i, for t> 0 and 7 >0