Problem Set

For Problems 1–4, list the first five terms of each sequence, and identify them as arithmetic or geometric.
1) An+1=An+4 for n≥1 and A1=-2

2) An+1=14An for n≥1 and A1=8

3) An+1=An-19 for n≥1 and A1=-6

4) An+1=23An for n≥1 and A1=6

For Problems 5–8, identify the sequence as arithmetic or geometric, and write a recursive formula for the sequence. Be sure to identify your starting value.
5) 14, 21, 28, 35, …

6) 4, 40, 400, 4000, …

7) 49, 7, 1, 17, 149, …

8) -101, -91, -81, -71, …

9) The local football team won the championship several years ago, and since then, ticket prices have been increasing $20 per year. The year they won the championship, tickets were $50. Write a recursive formula for a sequence that models ticket prices. Is the sequence arithmetic or geometric?

10)A radioactive substance decreases in the amount of grams by one-third each year. If the starting amount of the substance in a rock is 1,452 g, write a recursive formula for a sequence that models the amount of the substance left after the end of each year. Is the sequence arithmetic or geometric?