Set Math Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium
Write the set B={xโˆˆZ:โˆ’2โ‰คx<3}B = \{x \in \mathbb{Z} : -2 \le x < 3\} in roster notation.

Solution

  1. 1
    Parse the set-builder notation B={xโˆˆZ:โˆ’2โ‰คx<3}B = \{x \in \mathbb{Z} : -2 \le x < 3\}: we need all integers xx satisfying โˆ’2โ‰คx-2 \le x AND x<3x < 3.
  2. 2
    List integers from โˆ’2-2 upward, stopping before 3: โˆ’2,โˆ’1,0,1,2-2, -1, 0, 1, 2. The integer 3 is excluded because the condition is strict (x<3x < 3).
  3. 3
    Write in roster form: B={โˆ’2,โˆ’1,0,1,2}B = \{-2, -1, 0, 1, 2\}. Verify: โˆฃBโˆฃ=5|B| = 5 elements, consistent with the range from โˆ’2-2 to 22 inclusive.

Answer

B={โˆ’2,โˆ’1,0,1,2}B = \{-2, -1, 0, 1, 2\}
Set-builder notation describes elements by a property. Converting to roster notation means listing every element that satisfies the condition explicitly.

About Set

A well-defined collection of distinct, unordered objects called elements, described either by listing or by a membership rule.

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