Math Problem Statement

Identify the following sequences as arithmetic, geometric, or neither. For the arithmetic and geometric sequences, identify the growth pattern.

Solution

The question asks to identify whether the given sequences are arithmetic, geometric, or neither, and, for arithmetic and geometric sequences, to determine the growth pattern. Let us analyze each sequence:

Sequence Analysis:

(a) 12, 144, 1728,...

  • To check if it's arithmetic, calculate the difference between consecutive terms:
    14412=132144 - 12 = 132, 1728144=15841728 - 144 = 1584.
    Since the difference is not constant, it's not arithmetic.
  • To check if it's geometric, calculate the ratio between consecutive terms:
    14412=12\frac{144}{12} = 12, 1728144=12\frac{1728}{144} = 12.
    Since the ratio is constant (r=12r = 12), this is a geometric sequence with a growth pattern of multiplying by 12.

(b) 0, 5, 10, 15, 20, 25,...

  • To check if it's arithmetic, calculate the difference between consecutive terms:
    50=55 - 0 = 5, 105=510 - 5 = 5, 1510=515 - 10 = 5.
    Since the difference is constant (d=5d = 5), this is an arithmetic sequence with a growth pattern of adding 5.
  • It is not geometric because the ratio between terms (50,105\frac{5}{0}, \frac{10}{5}) is not consistent.

(c) 0, 4, 16, 36, 64,...

  • To check if it's arithmetic, calculate the differences:
    40=44 - 0 = 4, 164=1216 - 4 = 12, 3616=2036 - 16 = 20.
    The differences are not constant, so it's not arithmetic.
  • To check if it's geometric, calculate the ratios:
    40,164=4,3616=2.25\frac{4}{0}, \frac{16}{4} = 4, \frac{36}{16} = 2.25.
    The ratios are not constant, so it's not geometric either.
    This is neither arithmetic nor geometric.

(d) 1.5, 2.25, 3.375, 5.0625,...

  • To check if it's arithmetic, calculate the differences:
    2.251.5=0.752.25 - 1.5 = 0.75, 3.3752.25=1.1253.375 - 2.25 = 1.125.
    The differences are not constant, so it's not arithmetic.
  • To check if it's geometric, calculate the ratios:
    2.251.5=1.5\frac{2.25}{1.5} = 1.5, 3.3752.25=1.5\frac{3.375}{2.25} = 1.5.
    Since the ratio is constant (r=1.5r = 1.5), this is a geometric sequence with a growth pattern of multiplying by 1.5.

Summary of Results:

  • (a): Geometric, growth pattern = multiply by 12.
  • (b): Arithmetic, growth pattern = add 5.
  • (c): Neither arithmetic nor geometric.
  • (d): Geometric, growth pattern = multiply by 1.5.

Would you like me to explain any of these in greater detail?


Follow-up Questions:

  1. What are the formulas for the nn-th term of an arithmetic or geometric sequence?
  2. How can we classify a sequence as "neither arithmetic nor geometric"?
  3. Can a sequence be both arithmetic and geometric simultaneously? If so, under what condition?
  4. How do we calculate the sum of the first nn terms of an arithmetic sequence?
  5. How do we calculate the sum of the first nn terms of a geometric sequence?

Tip:

For any sequence, always check the first few terms to determine if there's a common difference (arithmetic) or ratio (geometric).

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Geometric Sequences
Sequence Classification

Formulas

Arithmetic sequence nth term: a_n = a_1 + (n-1)d
Geometric sequence nth term: a_n = a_1 * r^(n-1)

Theorems

Constant difference property of arithmetic sequences
Constant ratio property of geometric sequences

Suitable Grade Level

Grades 8-10