Question

If f(1) = 1 and f(n) = f(n-1)2 – 4 then find the value of f(4).

Answer 1

f(1) = 2

f(2) = -5f(2-1) = -5f(1) = -5(2) = -10

f(3) = -5f(3-1) = -5f(2) = -5(-10) = 50

So, f(4) = ?