Part 3 - Geometric Sequences

What does r stand for?

• Range

• Common Ratio

• Common Range

How do you find your common ratio?

• Subtract each term by its previous term

• Subtract each term by the next term

• Divide each term by its previous term

• Divide each term by the next term

Answer explanation

Determine if the sequence is a Geometric Sequence. If yes, find R (The common ratio).

• No

• Yes

  R = 4

• Yes

  R = -4

• Yes

  R = -1/4

Answer explanation

R = Each term divided by it's previous.

-4/1 = -4

16/-4 = -4

-64/ 16 = -4

Determine if the sequence is a Geometric Sequence. If yes, find R (The common ratio).

• No

• Yes

  R = 5

• Yes

  R = 1/2

• Yes

  R = 2

Answer explanation

R = Each term divided by it's previous.

HAS TO BE THE SAME EACH TIME!

10/5= 2

15/10 = 2/3

20/15 = 4/3

No the same, therefore it is NOT a Geometric Sequence

What are the next 3 terms of this sequence?

• -320, 1280, -5120

• 320, -1280, 5120

• 320, 1280, 5120

• -320,- 1280, -5120

Answer explanation

R = 4 here.

Multiply the last term by 4 to get the next term and so forth.

What are the next 3 terms of this sequence?

• 54, 162, 486

• 486, 162, 54

• 729, 364.5, 182.25

• -486, -162, -54

Answer explanation

R = 1/3 here.

Multiply the last term by 1/3 to get the next term and so forth.

What is the formula for a Geometric Sequence?

What is the Rule for this Geometric Sequence?

What is the 10th term?

(use the correct rule from the previous question)

• -268435456

• 268435456

• -4096

• 4096

What is the 8th term?

(Create the rule, then use to find this term)

• -1.875

• -30720

• -0.9375

• -61440

Answer explanation