Math Problem Statement

A sequence starts with 1/2, 1/4, 1/8, ..., a rule for this sequence and the next three terms; another sequence where the fourth term is -7, and find the next three and previous three terms; a sequence starting with 0, 5, ..., with a rule and two possible sets of next three terms based on different rules.

Solution

I can see the image you've uploaded contains some sequences and their corresponding questions. Let me summarize the questions and help with the solutions. Based on what I can read:

2. A sequence starts with 12,14,18,\frac{1}{2}, \frac{1}{4}, \frac{1}{8}, \dots

  • a. Give a rule that the sequence follows.

    • It looks like the rule is to multiply the previous term by 12\frac{1}{2} to get the next term.
  • b. Follow your rule to write the next three terms.

    • The next term after 18\frac{1}{8} is 18×12=116\frac{1}{8} \times \frac{1}{2} = \frac{1}{16}.
    • Continuing, 116×12=132\frac{1}{16} \times \frac{1}{2} = \frac{1}{32}.
    • Then, 132×12=164\frac{1}{32} \times \frac{1}{2} = \frac{1}{64}.
    • So, the next three terms are 116,132,164\frac{1}{16}, \frac{1}{32}, \frac{1}{64}.

3. A sequence of numbers follows the rule: multiply the previous term by -2 and add 3.

  • a. The fourth term is -7. Give the next three terms.

    • To find the next term, we apply the rule.
    • If the fourth term is 7-7: Next term=(7×2)+3=14+3=17\text{Next term} = (-7 \times -2) + 3 = 14 + 3 = 17
    • Then, for the term after 17: Next term=(17×2)+3=34+3=31\text{Next term} = (17 \times -2) + 3 = -34 + 3 = -31
    • Finally, for the next term: Next term=(31×2)+3=62+3=65\text{Next term} = (-31 \times -2) + 3 = 62 + 3 = 65
    • So, the next three terms are: 17,31,6517, -31, 65.
  • b. Give the 3 terms that came before -7 in the sequence.

    • To work backwards, we reverse the rule. If the rule is "multiply by -2 and add 3," to find previous terms, we subtract 3, then divide by -2.
    • The term before -7: Previous term=732=102=5\text{Previous term} = \frac{-7 - 3}{-2} = \frac{-10}{-2} = 5
    • The term before 5: Previous term=532=22=1\text{Previous term} = \frac{5 - 3}{-2} = \frac{2}{-2} = -1
    • The term before -1: Previous term=132=42=2\text{Previous term} = \frac{-1 - 3}{-2} = \frac{-4}{-2} = 2
    • So, the three terms before -7 are: 5,1,25, -1, 2.

4. A sequence starts with 0,5,0, 5, \dots

  • a. Give a rule and the next three terms for the sequence.

    • The rule appears to be: "Add 5 to each term."
    • So, starting from 0,50, 5:
      • 5+5=105 + 5 = 10
      • 10+5=1510 + 5 = 15
      • 15+5=2015 + 5 = 20
    • The next three terms are 10,15,2010, 15, 20.
  • b. Give a different rule and the next three terms for that rule.

    • A different rule could be: "Multiply each term by 2."
    • Starting from 0,50, 5:
      • 5×2=105 \times 2 = 10
      • 10×2=2010 \times 2 = 20
      • 20×2=4020 \times 2 = 40
    • The next three terms would be 10,20,4010, 20, 40.

If you'd like to go over any of the steps or concepts in more detail, feel free to ask!

5 Related Questions:

  1. What other rules can you find to generate new sequences starting from 00 and 55?
  2. Can you create a sequence that alternates between positive and negative numbers?
  3. How would you determine a rule if the sequence were decreasing instead of increasing?
  4. What happens to the terms if you add both a multiplication and an addition step to the rule?
  5. Can you identify any other real-world patterns that follow the rules of sequences?

Tip:

When working with sequences, always identify if the rule involves addition, multiplication, or both, and check if there is a constant pattern across the terms.

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Math Problem Analysis

Mathematical Concepts

Sequences
Arithmetic Progression
Geometric Progression
Recursive Rules

Formulas

a_n = a_{n-1} * r (geometric sequence)
a_n = a_{n-1} + d (arithmetic sequence)

Theorems

Geometric Series
Arithmetic Series

Suitable Grade Level

Grades 6-8