To determine whether each mapping diagram represents a
function, we use the
definition of a function:
> A
function is a relation where
each input (element in the domain) is associated with
exactly one output (element in the range).
> That means:
> - Every element in the left oval (domain) must have
at least one arrow (no missing mappings).
> -
No element in the domain can have
more than one arrow pointing to different elements in the range.
Let’s analyze each diagram one by one:
---
1)
- Domain: {0, 1, 2, 5, 6}
- Each element has
one arrow.
- No element maps to more than one value.
✔ Function
---
2)
- Domain: {2, 3, 4, 6, 9}
- Check each:
- 2 → 0
- 3 → 4 and 6 → both 0 and 4? Wait:
- 3 → 0
- 4 → 4
- 6 → 0 and 4? No — wait, let's look carefully:
- 6 → 0 and 6 → 4? Yes! There are two arrows from
6: one to 0 and one to 4.
✘ Not a Function (One input maps to two outputs)
---
3)
- Domain: {2, 8, 9}
- All map to
5 only.
- Even though multiple inputs go to same output, that’s fine.
✔ Function
---
4)
- Domain: {0, 1, 4, 9}
- Check:
- 0 → 2 and 3? Two arrows from 0 → 2 and 3 → yes!
- So, 0 maps to two values: 2 and 3.
✘ Not a Function
---
5)
- Domain: {1, 2, 4, 5, 9}
- Each has exactly one arrow.
- No duplicates.
✔ Function
---
6)
- Domain: {0, 6, 8}
- All three map to
6.
- Multiple inputs → same output: allowed.
✔ Function
---
7)
- Domain: {1, 2, 8}
- Each has one arrow:
- 1 → 0
- 2 → 5
- 8 → 9
- Only one arrow per input.
✔ Function
---
8)
- Domain: {0, 2, 4, 7}
- Check:
- 0 → 3
- 2 → 6
- 4 → 6
- 7 → 9
- Each input has
only one arrow.
- Multiple inputs (2 and 4) map to 6 — allowed.
✔ Function
---
✔ Final Answers:
1)
Function
2)
Not Function
3)
Function
4)
Not Function
5)
Function
6)
Function
7)
Function
8)
Function
---
🔍 Summary Rule:
> A mapping is a
function if
every input has exactly one output.
> If
any input has more than one output, it's
not a function.
Let me know if you'd like this formatted as a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of identifying relations and functions worksheet.