Question

If f(1)=4 f(2)=5 and f(n)=f(n-1) + f(n-2) then find the value of f(5)

Answer 1

substituting n by 5 gives;

f(5)=(5-1)+(5-2)=7

Answer 2

23

Explanation:

f(3) = f(2) + f(1) = 5 + 4 = 9

f(4) = f(3) + f(2) = 9 + 5 = 14

f(5) = f(4) + f(3) = 14 + 9 = 23