Question

If f is a function such that f(0) = 2, f(1) = 3 and f(x+2) = 2f(x) – f(x+1) for every real x then f(5) is

• A. 7
• B. 13
• C. 1
• D. 5

Answer 1

Answer: (B)

13

Answer 2

For x = 0, f(2) = 2f(0) – f(1) = 2 × 2 – 3 = 1,

for x = 1, f(3) = 2f(1) – f(2) = 6 – 1 = 5,

for x = 2, f(4) = 2f(2) – f(3) = 2 × 1 – 5 = -3, for x = 3, f(5)

= 2f(3) – f(4) = 2×5 – (-3)= 13