3. find f(2), f(3), f(4), and f(5) if f is defined recursively by f(0) = −1, f(1) = 2, and for n = 1, 2, … a) f(n + 1) = f(n) + 3f(n − 1). b) f(n + 1) = f(n)2f(n − 1). c) f(n + 1) = 3f(n)2 − 4f(n − 1)2. d) f(n + 1) = f(n − 1)∕f(n).