Chapter 6 - Exponential Functions and Sequences - 6.6 - Geometric Sequences - Exercises - Page 336: 1

First sequence is an arithmetic sequence while the second one is a geometric sequence.

In the first sequence, the difference between each pair of consecutive terms is same (equal to 2). So, it is an arithmetic sequence with common difference equal to 2. In the second sequence, the ratio between each pair of consecutive terms is same (equal to 2). So, it is a geometric sequence.