A sequence is defined recursively using the formula f(n + 1) = –0.5 f(n) . If the first term of the sequence is 120, what is f(5)?

f(1) = 120

f(1+1) = -0.5f(1) = -0.5*120 = -60

f(2+1) = -0.5f(2) = -0.5*-60 = 30

f(3+1) = -0.5f(3) = -0.5*30 = -15

f(4+1) = -0.5f(4) = -0.5*-15 = 7.5

 

So, f(5)=7.5