Question

A rule for the nth term of 22,9,-4,-17,-30

Answer 1

Answer: In Exercises 21 and 22, describe and correct the error in writing a rule for the nth term of the arithmetic sequence 22, 9, −4, −17, −30, . . ..

3. 1, −1, −3, −5, −7, . . . 4.

5. 5, 8, 13, 20, 29, . . . 6.

7. 36, 18, 9, —9, —9, . . . 8. 24

9. —1, —3, 1, —5, —3, . . . 10. 24 42

12, 6, 0, −6, −12, . . .

3, 5, 9, 15, 23, . . .

81, 27, 9, 3, 1, . . .

—1 , —1 , —5 , —7 , —3 , . . . 62662

21.

22. ✗

11. WRITING EQUATIONS Write a rule for the arithmetic sequence with the given description.

a. The first term is −3 and each term is 6 less than the previous term.

b. The first term is 7 and each term is 5 more than the previous term.

12. WRITING Compare the terms of an arithmetic sequence when d > 0 to when d < 0.

In Exercises 13–20, write a rule for the nth term of the sequence. Then find a20. (See Example 2.)

The first term is 22 and the common difference is −13.

an =−13+(n−1)(22) an =−35+22n

13. 12, 20, 28, 36, . . . 14. 15. 51, 48, 45, 42, . . . 16.

7, 12, 17, 22, . . .

27. a =−5,d=−—1

17 2 21 2

86, 79, 72, 65, . . . 11 511

29. USING EQUATIONS One term of an arithmetic sequence is a8 = −13. The common difference

is −8. What is a rule for the nth term of the sequence?

○A an = 51 + 8n ○B an = 35 + 8n ○C an=51−8n ○D an=35−8n

17. −1, −—3, —3, 1, . . . 18. 19. 2.3, 1.5, 0.7, −0.1, . . . 20.

−2, −—4, −—2, —4, . . . 11.7, 10.8, 9.9, 9, . . .

422 Chapter 8 Sequences and Series

✗

Use a1 = 22 and d = −13. a =a +nd

In Exercises 23–28, write a rule for the nth term of th

Step-by-step explanation: