📘 Class 11 Mathematics – Lesson 2: Functions
A function is a rule that assigns exactly one output for every input. In Lesson 2 of Class 11 Mathematics, students explore the definition, types, and representation of functions, which are the backbone of algebra and calculus.
Understanding functions helps build a strong foundation for future math topics like limits, derivatives, and integration.
🧠 Key Concepts Covered
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Definition of a Function: A relation where each input has one unique output
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Domain and Range: Input values (domain) and resulting values (range)
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Types of Functions:
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One-one (Injective)
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Onto (Surjective)
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Bijective (both one-one and onto)
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Constant, Linear, Quadratic, Polynomial, Exponential, etc.
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Function Notation: f(x)f(x), g(x)g(x), etc.
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Graphical Representation of Functions
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Composite Functions and Inverse Functions
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Even and Odd Functions
📚 Why This Lesson Is Important
Functions are used everywhere in math and real life—from calculating speed to modeling population growth. This lesson improves your understanding of how inputs and outputs relate, which is key in NEB exams and higher-level studies.
📥 View the PDF Notes
You have access to the full Class 11 Mathematics Chapter 2 notes with definitions, solved examples, and clear graphs.
💡 Exam Tip
To check if a graph represents a function, use the vertical line test: If a vertical line touches the graph at more than one point, it’s not a function.
