Question

If f(1)=1, f(2)=4 and f(n)=3f(n-1)-f(n-2) then find the value of f(4).

Answer 1

29

Explanation:

f(3)=3f(2)-f(1)=3x4-1=11

f(4)=3f(3)-f(2)=3x11-4=29