What you’ll learn
Identify functions from mappings.
Key idea
A function assigns exactly one output to each input in its domain; distinct inputs may share an output.
Shared outputs are allowed; each input must have exactly one assigned output, even if a student's conclusion happens to be correct.
Worked example
Classify examples and non-examples for the concept 'Identify functions from mappings'.
Classify relation {(-5,-5),(-4,-5),(-3,3)} as a function or not, with assignment evidence.
- Group assignments by their first coordinates in {(-5,-5),(-4,-5),(-3,3)}, not by repeated second coordinates.
- Function: each input has exactly one assigned output; shared outputs are allowed. Output -5 is shared but this alone cannot decide the function property.
Answer: Function — each input has exactly one assigned output; shared outputs are allowed.
Quick Check
Classify examples and non-examples for the concept 'Identify functions from mappings'.
Classify relation {(-5,-3),(-5,-5),(-4,-3)} as a function or not, with assignment evidence.