Class 9 Math Chapter 10 Graph of Functions – Complete Notes with Examples

 Class 9 Math Chapter 10 “Graph of Functions” introduces students to the basics of coordinate geometry and graph plotting. In this chapter, you will learn how to plot points on a coordinate plane, draw graphs of functions, and understand relationships between variables.

Graph of Functions is an important chapter in Class 9 Mathematics that helps students understand how algebraic equations are represented visually on a graph. This chapter builds a strong foundation for coordinate geometry and higher mathematics.

In this article, you will learn the concept of functions, Cartesian plane, graph plotting, solved examples, and practice questions, along with a PDF download link.

📌 What is a Function?

A function is a relation in which each input has exactly one output.

👉 Example:

f(x) = x + 2

If x = 1 → f(1) = 3

📌 Cartesian Plane

A Cartesian plane consists of two perpendicular lines:

X-axis (horizontal line)

Y-axis (vertical line)

👉 The point where they intersect is called the origin (0,0).

📌 Coordinates of a Point

A point on a graph is represented as (x, y).

👉 Example:

(2, 3) means:

x = 2 (horizontal movement)

y = 3 (vertical movement)

📊 Plotting a Function on Graph

To draw a graph:

Choose values of x

Find corresponding values of y

Plot the points on graph

Join the points

📈 Example Function

👉 Table of values:

x          y

0           2

1           3

2           4

👉 Plot these points and join them to form a straight line.

📊 Solved Examples

✅ Example 1:

Plot the graph of y = x + 1

👉 Solution:

Take values of x = 0, 1, 2

Find y values

Plot points and draw a straight line

✅ Example 2:

Find the coordinates when x = 3 for y = x + 2

👉 Solution:

y = 3 + 2 = 5

👉 Point = (3, 5)

📝 Practice Questions

Define a function

Plot graph of y = x + 3

Find value of y when x = 4 for y = x + 1

What is Cartesian plane?

Write coordinates of point (2,5)

You can download the complete notes from the link below:

https://drive.google.com/file/d/1285-FuT2WoFekv2MfPW5BKaal73kymnL/view?usp=drivesdk