find the first 4 terms of the sequence using the recursive definition f(1)=4 f(2)=7 and f(n)=f(n-1)+2f(n-2)

Answer 1

f(1) = 2 and f(2) = 7

f(n) = f(n-1) + 2f(n-2) for n ≥ 3

So, for n = 3, we have f(3) = f(2) + 2f(1) = 7 + 4 = 11

When n = 4, f(4) = f(3) + 2f(2) = 11 + 14 = 25

First four terms: 2, 7, 11, 25