Section 9.2

Arithmetic Sequences

OBJECTIVE 1

Arithmetic Sequence

Show that the sequence is arithmetic. List the first term and the common difference.

(a) 4, 2, 0, -2, . . .

(b) 4 1ns n

(c) 2 3nt n

OBJECTIVE 2

Find the twenty fourth term of the arithmetic sequence:

-3, 0, 3, 6, . . .

The sixth term of an arithmetic sequence is 26, and the nineteenth term is 78.

(a) Find the first term and the common difference.

(b) Give a recursive formula for the sequence.

(c) What is the nth term of the sequence?

OBJECTIVE 3

Find the sum of the first n terms of the sequence {4n + 2}

Find the sum: 52 + 57 + 62 + 67 + … + 122

Finding the Number of Seats in a Stadium

The first row of seats in a corner stadium section has 20 seats. There are 40 rows in the section with each row having two more seats than the row in front. How many seats are in that section of the stadium?