Unit 9 Review

Which is an arithmetic sequence?

• 1, 3, 5, 7, 9, ...

• 1, 2, 4, 8, 16, 32, ...

• 1, 1, 2, 3, 5, 8, 13, ...

Arithmetic sequences involve

• multiplication and division
• multiplication and addition
• addition and subtraction
• subtraction and division

What does a₁ represent?

• Any term

• First term

• Last term

Given the sequence:

25, 21, 17, 13,...

Write the explicit equation that models the sequence.

• a_n = -4n + 29

• a_n = 25 +(-4)(n-1)

• a_n = -25 +(-4)(n-1)

• a_n = 4n + 25

Write the explicit formula for the sequence -4, -6, -8, -10,...

• a_n = -4 + (-2)(n-1)

• a_n = 4 + (-2)(n-1)

• a_n = -4 - 2(n-1)

• a_n = -4 + 2(n-1)

Create the explicit formula for the sequence:
2, 8, 14, ...
(Hint:  Write your formula and then simplify it.)

• a_n=2+6n
• a_n=-6+6n
• a_n=6n-4
• a_n=4-6n

Write a recursive formula for the following sequence:

10, 5, 0, -5,...

• a₁= 10

  a_n= a_n-1 - 5

• a₁= 10

  a_n= a_n-1 + 5

• a₁= 10

  a_n= a_n (5)

• a₁= 10

  a_n= a_n-1 (5)

Write a recursive rule for the sequence 17, 1, -15, -31 . . .

• a_n = a_n-1 + 16
  a₁=17
• a_n = a_n-1 - 17
  a₁=17
• a_n = a_n-1 - 15
  a₁=17
• a_n = a_n-1 - 16
  a₁=17

Write the recursive formula for the following sequence?
6, 4, 2, 0, . . .

• a_n = -2n + 8
• a₁ =6, a_n = a_n - 1 - 2
• a₁ = 6, a_n = a_n-1 + 2
• a₁ = 6, a_n = a_n-1 - 2

Write the recursive formula for 6, 17, 28, 39, 50....

• a_n=a_n-1+11
  a₁=6
• a_n=a_n-1-4
  a₁=6
• a_n=a_n-1+9
  a₁=6
• a_n=a_n-1+6
  a₁=6