Arithmetic and Geometric Nth Term

The first three terms of an arithmetic sequence are 3, 11, and 19. Which function represents the sequence?

• a_n = 8 + 3(n-1)

• a_n = 8(3)^n-1

• a_n = 3 + 8(n-1)

• a_n = 3 + 8n

A geometric sequence has as its first three terms 48, 12, and 3. Which function represents the sequence?

• a_n = 48(1/4)^n-1

• a_n = 48 - (n-1)36

• a_n = 48(4)^n-1

• a_n = 3(4)^n-1

The fourth, fifth, and sixth terms of an arithmetic sequence are 56, 49, and 42. Which function represents the sequence?

• a_n = 56 - 7(n-1)

• a_n = 42 + 7(n-1)

• a_n = 77 - 7(n-1)

• a_n = 42(7)^n-1

An arithmetic sequence has a₁=2 and d=4. What is the Explicit Rule for a_n and use it to find the 20^th term.

• a_n = 2 - 4(n-1)

  a₂₀ = 82

• a_n = 2 + 4(n-1)

  a₂₀ = 78

• a_n = 2(4)^n-1

  a₂₀ = 2199023255552

• a_n = 4 + 2(n-1)

  a₂₀ = 42

A geometric sequence has a₁ = 3 and r = 2. What is the Explicit Rule for a_n and use it to find the 10th term.

• a_n = 3 + 2(n-1)

  a₁₀ = 21

• a_n = 2(3)^n-1

  a₁₀ = 39366

• a_n = 3(2)^n-1

  a₁₀ = 1536

• a_n = 2 + 3(n-1)

  a₁₀ = 29

Given the sequence 2, 8, 14, 20, 26, ... What is the common difference?

• 2

• 4

• 6

• 8

How many of these sequences have a common difference of -4?

-19, -15, -11, -7, -3,...

19, 15, 11, 7, 3...

3, 7, 11, 15, 19...

-3, 7, -11, 15, -19,...

• 0

• 1

• 2

• 3

What number follows 20 in this arithmetic sequence?

• 5

• 23

• 26

• 29

Find the missing term in the geometric sequence: 8, 20, 50, 125, _____.

• 75

• 200

• 250

• 312.5

Describe the pattern in the sequence. Find the next three terms.

13, 15, 17, 19,...

• Add 2; 23, 25, 27

• Multiply by 2; 38, 76, 152

• Add -2; 17, 15, 13

• Add 2; 21, 23, 25