Math Problem Statement

Identify the General Pattern

1.) 85, 79, 73, 67, 61,..... 2.) 15, 22, 29, 36,... 3.) 4, 8, 12, 16, 20,.... 4.) 1, 5, 11, 19, 29 5.) 8, 19, 34, 53, ....

Solution

Let's analyze the general patterns for each sequence:


1.) 85, 79, 73, 67, 61,...

  • This is an arithmetic sequence, where each term decreases by 6.
    • Difference: 8579=685 - 79 = 6, 7973=679 - 73 = 6, and so on.
    • General form: an=856(n1)a_n = 85 - 6(n-1)

Pattern: Decreasing by 6.


2.) 15, 22, 29, 36,...

  • This is an arithmetic sequence, where each term increases by 7.
    • Difference: 2215=722 - 15 = 7, 2922=729 - 22 = 7, and so on.
    • General form: an=15+7(n1)a_n = 15 + 7(n-1)

Pattern: Increasing by 7.


3.) 4, 8, 12, 16, 20,...

  • This is an arithmetic sequence, where each term increases by 4.
    • Difference: 84=48 - 4 = 4, 128=412 - 8 = 4, and so on.
    • General form: an=4+4(n1)a_n = 4 + 4(n-1)

Pattern: Increasing by 4.


4.) 1, 5, 11, 19, 29,...

  • This is a quadratic sequence where the second differences are constant.
    • First differences: 51=45 - 1 = 4, 115=611 - 5 = 6, 1911=819 - 11 = 8, and so on.
    • Second differences: 64=26 - 4 = 2, 86=28 - 6 = 2, and so on.
    • General form (quadratic): an=n2+n1a_n = n^2 + n - 1

Pattern: Quadratic pattern with second difference constant.


5.) 8, 19, 34, 53,...

  • This is another quadratic sequence, as the second differences are constant.
    • First differences: 198=1119 - 8 = 11, 3419=1534 - 19 = 15, 5334=1953 - 34 = 19.
    • Second differences: 1511=415 - 11 = 4, 1915=419 - 15 = 4.
    • General form (quadratic): an=2n2+5n+1a_n = 2n^2 + 5n + 1

Pattern: Quadratic pattern with constant second differences.


Would you like any further details or clarifications on any of these sequences?


Here are 5 related questions:

  1. What is the next term in the first sequence?
  2. Can you generalize the formula for the second sequence?
  3. How do you determine if a sequence is quadratic or arithmetic?
  4. What are the first 10 terms of the third sequence?
  5. How would you derive the quadratic form of the fourth sequence?

Tip: When analyzing sequences, always check for constant differences between terms; this helps to identify whether the sequence is arithmetic, geometric, or quadratic.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Quadratic Sequences
Algebra

Formulas

Arithmetic sequence formula: a_n = a_1 + d(n-1)
Quadratic sequence formula: a_n = an^2 + bn + c

Theorems

General formula for arithmetic sequences
Quadratic difference method for sequences

Suitable Grade Level

Grades 6-8