Math Problem Statement

The first four terms of the sequence are 2, 5, 12.5, 31.25,... Determine the type of sequence represented. Does the sequence have a common difference or a common ratio? State the value of the common difference or common ratio. State the next term in the sequence.

Solution

The sequence provided in the image is:

2,5,12.5,31.25,2, 5, 12.5, 31.25, \dots

1. Determine the type of sequence represented:

To identify the type of sequence, let's see if there is a common difference (arithmetic sequence) or a common ratio (geometric sequence).

  • The ratio of the second term to the first term is: 52=2.5\frac{5}{2} = 2.5
  • The ratio of the third term to the second term is: 12.55=2.5\frac{12.5}{5} = 2.5
  • The ratio of the fourth term to the third term is: 31.2512.5=2.5\frac{31.25}{12.5} = 2.5

Since there is a constant ratio of 2.5 between consecutive terms, this is a geometric sequence.

2. Does the sequence have a common difference or a common ratio?

The sequence has a common ratio.

3. State the value of the common difference or common ratio:

The common ratio is 2.52.5.

4. State the next term in the sequence (do not round):

To find the next term, multiply the last term by the common ratio: 31.25×2.5=78.12531.25 \times 2.5 = 78.125 Thus, the next term is 78.125.


Do you want more details or have any questions?

Here are 5 related questions to expand on this:

  1. How do you identify whether a sequence is arithmetic or geometric?
  2. What is the general formula for the nn-th term of a geometric sequence?
  3. How can you find the sum of the first nn terms of a geometric sequence?
  4. What are the key differences between arithmetic and geometric sequences?
  5. How can you apply sequences in real-world problems?

Tip: In a geometric sequence, multiplying any term by the common ratio gives the next term, while dividing gives the previous term.

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Math Problem Analysis

Mathematical Concepts

Geometric Sequence
Common Ratio
Sequences

Formulas

nth term of geometric sequence: a_n = a_1 * r^(n-1)

Theorems

Common Ratio in Geometric Sequence

Suitable Grade Level

Grades 8-10