Series and Sequences Review

Which sequence is NOT an arithmetic sequence?

• -7, -13, -19, -25,...

• -10, -6, -2, 2,..

• 6, 8, 10, 12,...

• 3, 15, 75, 375,...

Which sequence is NOT an arithmetic sequence?

• 12, 18, 24, 30,...

• 10, 3, -4, -11,...

• 2, 4, 8, 16,...

• 16, 20, 24, 28,...

We will start with the explicit formula. Given the following sequence, state the first term and common difference.

Example 1:          4, 7, 10, 13, 16, …

Now, find the term BEFORE term 1 (term 0).

Example 1:          4, 7, 10, 13, 16, …

•  1

•  4

•  7

•  0

Now, write the explicit formula for the given sequence.

Example 1:          4, 7, 10, 13, 16, …

State the common difference:

Example 2: 21, 19, 17, 15, …

Write an explicit rule to model the following sequence:

Example 2: 21, 19, 17, 15, …

• $a_n=21-2n$
  

• $a_n=21+2n$
  

• $a_n=23+2n$

• $a_n=23-2n$
  

Write and explicit rule to model the following sequence:

Example 3:        -12, -7, -2, …

Find the 26th term in the arithmetic sequence: 20, 26, 32, 38, ...

• 182
• 176
• 170
• -118