6 min read
Function or Not
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
Choose Your Level
Function or Not
What is it?
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
In simple words
- Each first component appears once.
- input unique
- one output per input
- domain = inputs
Important terms
Function Or Not: Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
What you should learn
- Define and explain function or not.
- Apply function or not to a focused FBISE question.
- Check the answer for correct terms, evidence, working, and units.
Examples
- input unique
- one output per input
- domain = inputs
CORE UNDERSTANDING
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
EXAM APPLICATION
State the correct term, connect it to the chapter rule or evidence, and use a clear example or calculation.
Recommended for Class 10
Full school-level explanation
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
Learn the idea, then use it:
WHAT — FUNCTION OR NOT
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
HOW — Use the idea
Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check the result.
CORE UNDERSTANDING
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an input with two outputs is not.
Remember
- input unique
- one output per input
- domain = inputs
Examples
- input unique
- one output per input
- domain = inputs
- FUNCTION OR NOT: Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeat
EXAM APPLICATION
State the correct term, connect it to the chapter rule or evidence, and use a clear example or calculation.
Remember
- correct term
- chapter link
- clear application
Examples
- Define first
- Show the rule or evidence
- Check units, labels, and conclusion
Remember
- input unique
- one output per input
- domain = inputs
- keep the ideas separate
- input unique
- one output per input
- domain = inputs
- correct term
Deeper understanding
Go beyond memorising Function or Not. Connect the definition to reasons, relationships, exceptions, and exam wording.
Common mistakes
Exam focus
Core Idea
Key Points
Simple Check
How to Answer
Exam focus
Quick revision
- input unique
- one output per input
- domain = inputs
- keep the ideas separate
- Function Or Not: Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps t
- WHAT — FUNCTION OR NOT: Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps t
Do not merge function or not with a neighbouring idea that uses a different definition, rule, or method.
For long answers on Function or Not: define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- input unique
- one output per input
- domain = inputs
- keep the ideas separate
Important formulas
- input unique
- one output per input
- domain = inputs
Common exam traps
- Do not merge function or not with a neighbouring idea that uses a different definition, rule, or method.
- Do not invent a formula, fact, unit, or diagram label that the chapter does not support.
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Do not merge function or not with a neighbouring idea that uses a different definition, rule, or method.
- Mistake
Do not invent a formula, fact, unit, or diagram label that the chapter does not support.
- Mistake
Do not merge function or not with a neighbouring idea that uses a different definition, rule, or method.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
input unique
one output per input
domain = inputs
keep the ideas separate
Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an i
domain = inputs
- Definition
- Each first component appears once. R2 = {(2,3),(6,1),(8,3),(6,5)} is not a function because 6 maps to 1 and to 5. Repeating an output is allowed; repeating an i
- Formula
- domain = inputs
- Example
- input unique
- Critical warning
- Do not merge function or not with a neighbouring idea that uses a different definition, rule, or method.
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Exam Practice
Define
Q1. Define Function or Not.
Explain
Q2. Explain: CORE UNDERSTANDING.
Example
Q3. Give one clear example of Function or Not and say why it fits.
Mistake
Q4. State one common mistake students make about Function or Not.
Exam note
Q5. Write a short exam note on Function or Not: definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.