A) use differentiation to find a power series representation for f(x) = 1 (9 + x)2 . f(x) = ∞ n = 0 what is the radius of convergence, r? r = (b) use part (a) to find a power series for f(x) = 1 (9 + x)3 . f(x) = ∞ n = 0 what is the radius of convergence, r? r = (c) use part (b) to find a power series for f(x) = x2 (9 + x)3 . f(x) = ∞ n = 2 what is the radius of convergence, r? r =