Question

What is the explicit rule for the geometric sequence?
a1=4; an=1/3 x an-1

Answer 1

(c) an = 4·(1/3)^(n-1)

Explanation:

The explicit rule for a geometric sequence with first term a1 and common ratio r is ...

an = a1·r^(n-1)

The factor in the recursive rule tells you the common ratio is 1/3, so the explicit rule is ...

an = 4·(1/3)^(n-1) . . . . . . matches choice C