2. Lesson 3A: Arithmetic Sequences

3. Ex 1: Can you find a pattern and use it to guess the next term? A) 7, 10, 13, 16,... B) 14, 8, 2, − 4,... C) 1, 4, 9, 16,...

4. Definition: An arithmetic sequence is a sequence made by adding or subtracting the same value each time.

5. a, a + d, a + 2d, a + 3d … d = common difference a = 1st term n th term: Explicit Formula

6. Ex 2: So which examples were arithmetic sequences? Identify d and a. Write the formula for a n. A) 7, 10, 13, 16,... B) 14, 8, 2, − 4,... C) 1, 4, 9, 16,...

7. Ex 3: The formula describes an arithmetic sequence. What are the first 4 terms in the sequence?

8. Ex 4: Find the first 4 terms and the n th term: a = 2 & d = 3 a 1 = a 2 = a 3 = a 4 = a n =

9. 9, 4, –1, –6, –11, … a = d = a n = Ex 5: Write an explicit formula for the following sequence:

10. Recursive Formula A recursive formula is a formula that expresses any term a n in terms of the previous term a n−1

11. Ex 6: Write a recursive formula for the following sequence: -2, -6, -10, -14, …

12. Cool Math! https://www.youtube.com/watch?v=wTl w7fNcO-0 https://www.youtube.com/watch?v=SjS HVDfXHQ4 https://www.youtube.com/watch?v=ahXI MUkSXX0