What is aRelation?
• A relation is a set of ordered pairs (x, y)
• Defines a connection between elements of two
sets
• Can be represented as: {(x , y ), (x , y ), ...}
₁ ₁ ₂ ₂
• Example: {(1, 2), (2, 3), (3, 4)}
3.
Real-Life Examples ofRelations
• Student and their grades
• Countries and their capitals
• Employees and their salaries
Domain and Rangeof a Relation
• Domain: All first elements (x-values)
• Range: All second elements (y-values)
• Example: Relation {(1, 2), (2, 3), (3, 4)}
• Domain = {1, 2, 3}, Range = {2, 3, 4}
6.
What is aFunction?
• A function is a special type of relation
• Every element in domain maps to exactly one
element in range
• No element in domain has more than one image
in range
7.
Examples of Functions
•f(x) = 2x + 3 → Linear Function
• f(x) = x² → Quadratic Function
• f(x) = √x → Radical Function
How to Identifya Function?
• Check if any input has more than one output
• Graphically: Use Vertical Line Test
• If any vertical line intersects the graph more than once, it's not a function
10.
Domain and Rangein Functions
• Domain: All possible inputs
• Range: All possible outputs
• Example: f(x) = x², Domain: All real numbers, Range: y ≥ 0
11.
Different Representations ofFunctions
• 1. Equation Form (y = f(x))
• 2. Table of Values
• 3. Mapping Diagram
• 4. Graph
Checking if Relationis a Function
• Method 1: Check for repeated inputs with different outputs
• Method 2: Use the Vertical Line Test
23.
Graphing Functions
• Plotpoints from a table of values
• Connect the points smoothly for continuous functions
24.
Summary of KeyPoints
• Relations vs Functions
• Domain and Range
• Types and Representations
• Applications
25.
Practice Problems
• Determinewhether the following are functions:
• 1. {(1, 2), (2, 3), (3, 4)}
• 2. {(1, 2), (1, 3), (2, 4)}
• Find domain and range for f(x) = x² - 1