Math Problem Statement

Write down all the members of the following sets: (i) A = {x ∈ Z : 0 ≤ x < 7}, (ii) B = {x ∈ Z : -1 < x ≤ 2}, (iii) C = {x ∈ Z : x = -(-1)^n + 1 for some integer n}, (iv) D = {x ∈ Z : -2 < x < 4}

Solution

Let's go through the sets one by one and list all their members.

  1. Set A: A={xZ:0x<7}A = \{x \in \mathbb{Z} : 0 \leq x < 7\}

    • This set includes all integers xx such that 0x<70 \leq x < 7.
    • The members of set AA are: {0,1,2,3,4,5,6}\{0, 1, 2, 3, 4, 5, 6\}.
  2. Set B: B={xZ:1<x2}B = \{x \in \mathbb{Z} : -1 < x \leq 2\}

    • This set includes all integers xx such that 1<x2-1 < x \leq 2.
    • The members of set BB are: {0,1,2}\{0, 1, 2\}.
  3. Set C: C={xZ:x=(1)n+1 for some integer n}C = \{x \in \mathbb{Z} : x = -(-1)^n + 1 \text{ for some integer } n\}

    • This set involves the formula x=(1)n+1x = -(-1)^n + 1 where nn is an integer. We can find the values of xx by substituting values of nn:
      • When n=0n = 0: x=(1)0+1=1+1=0x = -(-1)^0 + 1 = -1 + 1 = 0
      • When n=1n = 1: x=(1)1+1=1+1=2x = -(-1)^1 + 1 = 1 + 1 = 2
      • When n=2n = 2: x=(1)2+1=1+1=0x = -(-1)^2 + 1 = -1 + 1 = 0 (Repeats, so cycle continues)
    • Therefore, the members of set CC are: {0,2}\{0, 2\}.
  4. Set D: D={xZ:2<x<4}D = \{x \in \mathbb{Z} : -2 < x < 4\}

    • This set includes all integers xx such that 2<x<4-2 < x < 4.
    • The members of set DD are: {1,0,1,2,3}\{-1, 0, 1, 2, 3\}.

Let me know if you need further details or explanations. Here are some related questions you might want to explore:

  1. How can you determine the range of a set if given different inequalities?
  2. What happens if you change the boundaries in the set definitions (e.g., from closed intervals to open intervals)?
  3. How would set CC change if you adjusted the formula slightly?
  4. Can you represent any of these sets using a union or intersection of other sets?
  5. What are the general properties of the integers that belong to set AA?

Tip: When dealing with set definitions involving formulas, start by plugging in small integer values to identify patterns or cycles.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Inequalities
Integer Sequences

Formulas

Set A: 0 ≤ x < 7
Set B: -1 < x ≤ 2
Set C: x = -(-1)^n + 1
Set D: -2 < x < 4

Theorems

Set Theory

Suitable Grade Level

Grades 6-9