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Question

Salazar Ramos

04/22/2024 · Primary School

What is the next number in the sequence below?

5

3

9

13

23

Answer
expertExpert-Verified Answer

Gibbs Parry
Qualified Tutor
5.0 (50votes)

31

Solution

UpStudy Free Solution:

 

To find the next number in the sequence \(5, 3, 9, 13, 23\), let's first look at the differences between consecutive terms:

 

\(3 - 5 = - 2\)

\(9 - 3 = 6\)

\(13 - 9 = 4\)

\(23 - 13 = 10\)

 

The differences between the terms are: \(- 2, 6, 4, 10\).

 

Now, let's look at the differences between these differences:

 

\(6 - ( - 2) = 8\)

\(4 - 6 = - 2\)

\(10 - 4 = 6\)

 

The second-level differences are: \(8, - 2, 6\).

 

To see if there's a pattern, let's look at the differences between these second-level differences:

 

\(- 2 - 8 = - 10\)

\(6 - ( - 2) = 8\)

 

The third-level differences are: \(- 10, 8\).

 

It appears that there might be a repeating pattern in the differences. Given the differences we have:

 

- First-level differences: \(- 2, 6, 4, 10\)

- Second-level differences: \(8, - 2, 6\)

- Third-level differences: \(- 10, 8\)

 

If we assume the pattern continues, the next second-level difference should be \(- 2\) (since \(8, - 2, 6\) appears to be a repeating pattern).

 

Adding \(- 2\) to the last first-level difference (which is \(10\)):

 

\[10 + ( - 2) = 8\]

 

Now, add this to the last term in the sequence (which is \(23\)):

 

\[23 + 8 = 31\]

 

So, the next number in the sequence is \(31\).

 

Supplemental Knowledge

 

Understanding sequences involves recognizing patterns in the differences between consecutive terms. Here are some key concepts that can help:

 

1. Arithmetic Sequences:

- An arithmetic sequence has a constant difference between consecutive terms.

- Example: \(2, 5, 8, 11, \ldots \) (common difference = 3).

 

2. Geometric Sequences:

- A geometric sequence has a constant ratio between consecutive terms.

- Example: \(3, 6, 12, 24, \ldots \) (common ratio = 2).

 

3. Difference Sequences:

- For more complex sequences, examining the differences between terms can reveal patterns.

- First-level differences are the differences between consecutive terms of the original sequence.

- Second-level differences are the differences between consecutive first-level differences.

 

4. Higher-Level Differences:

- Sometimes it’s necessary to look at second or even third-level differences to identify a pattern.

- If higher-level differences form a repeating pattern or become constant, it can help predict future terms.

 

5. Example Analysis of Differences:

- Consider the sequence \(1, 4, 9, 16\).

- First-level differences: \(3, 5, 7\).

- Second-level differences: \(2\), which is constant.

 

Deciphering complex sequences can be both daunting and gratifying - it takes both practice and hard work! But once you do find hidden patterns, the reward can be immense! UpStudy offers assistance for this and many other mathematical topics!
UpStudy is your go-to platform for solving math and other academic problems with ease, featuring AI-powered explanations and step-by-step solutions across numerous subjects such as chemistry, physics, biology and more. 

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