Question

Use the explicit rule given to write recursive rule for the geometric sequence:

Answer 1

Answer:

Option B

Step-by-step explanation:

A) a1 = 3

a2 = 3×20

an = 3 × 20^(n-1)

B) a1 = 20

a2 = 20×3

an = 20 × 3^(n-1)

C and D are not geometric

Answer 2

Answer:

  see below

Step-by-step explanation:

You know the relationship between the explicit rule and the recursive rule for a geometric sequence is ...

  $\text{explicit rule: }a_n=a_1\cdot r^{n-1}\\\\\text{recursive rule: }a_n=a_{n-1}\times r,\ \text{ a_1 is the same}$

The given explicit rule tells you a1 = 20, r = 3, so you know the recursive rule is the one shown below.