Arithmetic Sequences Problem Solving

Which of the following sequence is NOT an arithmetic?

• 25, 13, 1, –11, –23, . . .

• 9, 15, 21, 27, 33, . . .

• –12, –4, 4, 12, 20, 28, . . .  

• –4, 5, 18, 35, 56, 81, . . .

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

• 182

• 176

• 170

• -118

Find the 25th term of the sequence if a₁ = 5 and d = 0.5

• 18

• 17

• 15

• 14

Which sequence is NOT an arithmetic sequence?

• -7, -13, -19, -25,...

• -10, -6, -2, 2,..

• 6, 8, 10, 12,...

• 3, 15, 75, 375,...

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, …

Write and explicit rule to model the following sequence: