Summation

1. Tell whether each sequence is arithmetic, geometric, or neither. a. 1, 5, 9, 13, . . . b. 2, 6, 18, 54, . . . c. 1, 1, 2, 3, 5, 8, . . . d. 16, 4, 1, 0.25, . . . e. ?1, 1, ?1, 1, . . . f. 5.6, 2.8, 0, ?2.8, . . . 2. Find the common difference, d, for each arithmetic sequence and the common ratio, r, for each geometric sequence. a. 6, 11, 16, 21, . . . b. 100, 10, 1, 0.1, . . . c. 1.5, 1.0, 0.5, 0, ?0.5, . . . d. 0.0625, 0.125, 0.25, . . . e. ?1, 0.2, ?0.04, 0.008, . . . f. ?4, ?3.99, ?3.98, . . . 3. Write the first six terms of each sequence, starting with u1. a. u1 ? ?18 b. u1 ? 0.5 un ? un?1 ? 6 where n ? 2 un ? 3un?1 where n ? 2 c. u1 ? 35.6 d. u1 ? 8 un ? un?1 ? 4.2 where n ? 2 4. Write a recursive formula to generate each sequence. Then find the indicated term.