The function f(n) = 3f(n-2) - f(n-1), where f(2) = 3 and f(1) = -1. What is the value of f(5)?
function
\(f_3=-f_2+3f_1=-3+3*(-1)=-6\\ f_4=-f_3+3f_2=6+3*3=15\\f_5=-f_4+3f_3=-15+3*(-6)=-33\)
