Discrete Structure - Old Questions

17. Solve the recurrence relation an = 2a_n-1 + 2a_n-2 + 2a_n-3 for n ≥ 3, a₀ = 3, a₁ = 6 and a₂ = 9.

OR

Find the explicit formula for the Fibonacci numbers. Use f_n = f_n-1 + f_n-2 as recursive condition and

f₀ = 0 and f₁ = 1 as initial condition.