[sin (1) f(x) = {sin Let f(x) = () if x # 0, if x = 0; 0 and let {xn} be sequence defined by 2 Xn = (2n + 1) (a) Express f in terms of xn. (b) Evaluate f(xn) when n = 1,2,3,..., n. (c) Hence, obtain both lim xn and lim f(xn). n 818