Pre-CalculusSection 8.2B

Arithmetic Sequences

Sum of a Finite Arithmetic Sequence

The sum of a finite arithmetic sequence with n terms if given by:

1. Find the sum.

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

2. Find the sum.

Of the integers from 1 to 100.

Partial Sum

When you find the sum of a set number of terms.

Use the same formula

3. Find the 150th partial sum of the arithmetic sequence

5, 16, 27, 38, 49, …

4. Find the 50th partial sum of the arithmetic sequence

- 6, - 2, 2, 6, ….

5. Find the 100th partial sum of the given arithmetic sequence.

a1 = 15 a100 = 307

Find the partial sum

6.

100

1

2n

n

Find the partial sum

7.

100

51

7n

n

8. An auditorium has 20 rows of seats. There are 20 seats in the 1st row, 21 seats in the 2nd row, 22 seats in the 3rd row, and so on. How many seats are there in all 20 rows?

9. A small business sells $10,000 worth of sports merchandise its first year. The owner of the business has set a goal of increasing annual sales by $7500 each year for 19 years. Assuming this goal is met, find the total sales during the first 20 years this business is in operations.

Homework:

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