Sequences and Series Precalculus

Is the sequence 2, 4, 12, 48,... geometric?

• yes
• no

Is the sequence arithmetic: 37, 31, 25, 19, ...

• Yes
• No

5, 15, 45, 135 is a ...

• Geometric sequence with r = 3

• Geometric sequence with r = 1/3

• Arithmetic sequence with d = 10

• Arithmetic sequence with d = 3

Write a formula for the following sequence:

5, 8, 11, 14, 17...

• a_n = 3n + 2

• a_n = 8 - 5n

• a_n = 5(3)^n-1

• a_n = 5 + 3n

Write a formula for the following sequence:

4, 12, 36, 108...

• a_n = 4(3^n-1)

• a_n = 4(3ⁿ)

• a_n = 4+3n

• a_n = 4(3n)

Write a formula for the following sequence:

2, 8, 14, ...

• a_n = 2 + 6n

• a_n = - 6 + 6n

• a_n = 6n - 4

• a_n = 4 - 6n

What is the 100th term in the sequence a_n = 4n-12

• 388

• 40012

• -388

• 100

Given a₁= 5 and d= 2 find a₆

• 13
• 10
• 15
• 17

Find a₁₈ for the following geometric sequence,

-3, 6, -12, 24,,,

• -37

• -786,432

• 393,216

• 258,280,326

• 2400

• 2450

• 4800

• 9700