Sequences and Series

5, 10, 15, 20, 25, ...

Is this sequence Arithmetic, Geometric, or neither?

• Arithmetic (Common difference, d=5)

• Geometric (Common ratio, r=2)

• Neither

Identify the common difference (d) for following Arithmetic sequence.

10, 20, 30, 40, 50, 60, ...

• 10

• 11

• 12

• 20

Find the 22nd term of the following Arithmetic sequence.

5, 8, 11, 14, ...

a_{n =} a₁ + (n-1)d

• 14

• 68

• 63

• 71

Find an explicit rule (general rule) for the nth term of the following Arithmetic sequence.

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

a_n = a₁ + (n-1)d

• a_n = 15 + (n - 1)4

• a_n = -15 + (n - 1)4

• a_n = -15 + (n - 1)3

• a_n = 4n - 19

The Arithmetic sequence 28, 34, 40, 46, 52, ... , 82, 88, has 11 terms. Find sum of this sequence.

S_n = n ( a_{1 +} a_n)/2

• 650

• 683

• 638

• 700

The next two terms of the sequence: 4, 7, 10, 13, ... are

• 15, 18

• 17, 20

• 16, 20

• 16, 19

Identify the common ratio for the following Geometric sequence.

3, 9, 27, 81, ...

r = a₂/a₁

• 6

• 5

• 4

• 3

Find the 13th term for the following Geometric sequence.

2, 6, 18, 54, ...

a_n = a₁ (r)^n-1

• 1062882

• 3188646

• 354294

• Ø

The next two terms of the geometric sequence

8, 4, 2, 1, ...

• 1/3, 1/4

• 1/2, 1/4

• 1/4, 1/7

• 1/8, 1/6

What is the explicit rule for the sequence?

11, 22, 44, 88, ...

a_n = a₁(r)^n-1

• a_n = 2(11)^n-1

• a_n = 11(11)^n-1

• a_n = 11(2)^n-1

• a_n = 11 * 2