Answer:
D. f(1) = 4, f(n) = –1/2f(n – 1) for n > 1
Step-by-step explanation:
We assume your sequence is supposed to be ...
4, -2, 1, -1/2, 1/4, ...
This has no common difference, but it has a common ratio of -1/2. That is, the first term is 4, and each successive term is -1/2 times the previous one. The function is described by the recursive formula ...
f(1) = 4;
f(n) = -1/2·f(n-1)
