Question

What are the first three terms of the sequence modeled by the recursive function an=1/2a n-1, when a1=1?

Answer 1

The recursion is a_n = (1/2) a_{n-1} with a1 = 1.
So a1 = 1, a2 = (1/2)·1 = 1/2, a3 = (1/2)·(1/2) = 1/4.

First three terms: 1, 1/2, 1/4.