RELATION

Relation

Definition Of Relation

A set of input and output values, usually represented in ordered pairs, refers to a Relation.

More about Relation

Relation is generally represented by a mapping diagram and graph

Example of Relation

The mapping diagram of the relation {(1, 2), (3, 6), (5, 10)} is shown below.

Example of Relation

Video Examples: Relations and Functions

Solved Example on Relation

Ques: Choose a graph that represents the relation {(3, - 4), (5, - 4), (- 6, - 4), (2, 3)}.

Choices:

A. Graph 3
B. Graph 1
C. Graph 4
D. Graph 2
Correct Answer: D

Solution:

Step 1: Graph each ordered pair on a coordinate plane
Step 2: The graph that represents the relation {(3, - 4), (5, - 4), (- 6, - 4), (2, 3)} is Graph 2
Example on Relation

Quick Summary

A relation is a set of ordered pairs.
Relations can be represented by mapping diagrams and graphs.

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⚠️ Common Mistakes

Confusing relations with functions (not all relations are functions).
Incorrectly plotting ordered pairs on a graph.

🌍 Real-World Uses

Tracking customer purchases in a store (customer ID, purchase amount)
Matching students to their test scores (student name, score)
Mapping cities to their populations (city name, population)

🍎 Teacher Insights

Use real-world examples to illustrate relations. Emphasize the difference between relations and functions early on.

🎓 Prerequisites

Set Theory
Ordered Pairs
Coordinate Plane

Check Your Knowledge

Q1: Which of the following represents a relation?

A. y = x + 1 B. {(1, 2), (3, 4), (1, 5)} C. f(x) = x^2 D. All of the above

Frequently Asked Questions

Q: What is a mapping diagram?
A: A mapping diagram visually represents the relationship between input and output values in a relation.