A function is given by the ordered pairs (2, 5), (4, 9), (6, 5) and (8, 1). What is its range?
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Answer: B
Correct answer: {1, 5, 9}. The range is every second coordinate that appears: 5, 9, 5 and 1. Listing each value once gives {1, 5, 9}.
- A: This keeps only the smallest and largest outputs and leaves out 5, which is also produced.
- B (correct): The range is the set of outputs produced: 5, 9, 5 and 1, which is {1, 5, 9} once the repeat is listed once.
- C: These are the inputs, so this is the domain, not the range.
- D: This mixes inputs and outputs together; the range uses only the outputs.