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RS Aggarwal Solutions Class 12 Chapter-9 Continuity and Differentiability

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Class 12 RS Aggarwal Chapter-9 Continuity and Differentiability Solutions - Free PDF Download

Continuity and Differentiability Class 12 RS Aggarwal is an important topic for the students preparing for the Class 12th Board examination. The textbook provides stepwise solutions for the students so that they can easily solve various problems. It will be a great resource for practise and revision purposes that will level them up in the growing competitive scenario. The concepts that are part of this chapter also seem to be helpful for future studies. The simple and easy interface of the exercise with questions and solutions make it uncomplicated to grasp the topic. Experts from the concerned discipline are involved in framing the chapter along with a detailed explanation. So, by following the RS Aggarwal Class 12 Maths Chapter 9 Solutions PDF by Vedantu students can excel in the examination with higher grades.

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Class 12 RS Aggarwal Chapter-9 Continuity and Differentiability Solutions - Free PDF Download

Concept of Continuity and Differentiation

Continuity and Differentiation explained in RS Aggarwal Solutions Class 12 Maths Ch 12 is one of the vital concepts for students preparing for board exams. It deals with concepts like the derivative of functions, continuity of certain points, continuity of given intervals, and others. 


The continuity of a function determines the attributes of a function and its functional values.  In a given domain or interval, a function is accepted as continuous if the curve has no breaking points or missing points. That is the curve has to be continuous at every point in its domain. 


A function f(x) is said to be continuous at a point x= y if it meets the following three conditions.

  1.  f(y) is continuous if the value of f(y) is finite

  2.  f(x) limx→af is continuous at the point if the right-hand limit is the same as that of the left-hand limit. Therefore, R.H.S = L.H.S. 

  3.  lim x→af f(x)= f(y)

In a given interval, f(x) can only be continuous if it is equal to x1,x2. All the conditions need to be satisfied with each and every point. 


In differentiation, f(x) is said to be differentiable at the point x = y if the derivative f ‘(y) exists at each point in its interval or domain.

The differentiability formula is given by

f’ (y) = {f(y+h)−f(y)}/ h


State the Differentiability Formula for the Derivatives of the Basic Trigonometric Function

In a particular point, if a function is continuous, then the function can be differentiable at any point x=y, in its domain. However, the vice-versa may not be true every time. 


In the given table, the derivatives of the basic trigonometric functions are explained below from the aspect of differentiability formula: 


d/dx (sin x) →

cos x

d/dx (cos x) →

-sin x

d/dx (tan x)→

sec²x

d/dx (cot x)→

cosec²x

d/dx (sec x)→

sec x tan x

d/dx (cosec x)→

Cosec x cot x


Highlights of the RS Aggarwal Solutions for Class 12 Continuity and Differentiability Chapter

  • The meaning of continuous functions has been explained in this chapter with reference to graphs. 

  • The distinction between continuous and discontinuous functions can be expressed with the help of a graph.

  • By practising the solutions given in this chapter, one can understand the proofs of different theorems and the behaviour of continuous functions when these are subjected to algebraic calculations. 

  • Students can study several corollaries extracted from theorems and prove them. 


Solved Exercise Questions of RS Aggarwal Class 12 Chapter 9 

Question: 

f(x) = x²

LHL at x = 2

Limx→2 f(x)= Limx→0 f(2-h)

                    = Limx→0 f(2 - h)²

                    = Limx→0 f (h² - 4h + 4)

                    = (0-4) x (0+4)

                    = 4

RHL at x = 2

Limx→2 f(x)= Limx→0 f(2-h)

                    = Limx→0 f (2 - h)²

                    = Limx→0 f (h² - 4h + 4)

                    = (0-4) x (0+4)

                    = 4

Therefore, fx is continuous at 2.


Students studying this maths topic should know about the relationship between differentiability and continuity. This will be an interesting thing to learn in their course of the syllabus.

  • If x is a differentiable function, then x has to be continuous. 

  • A function can be continuous without it being differentiable.


Exercise-Wise Discussion of RS Aggarwal Solutions for Class 12 Chapter 9 Continuity and Differentiability

  • In the exercise solutions of 9A, you will learn about the conditions required to prove whether a function is continuous or discontinuous by checking the mandatory condition. 

  • You have to check the continuity of more complex functions in the exercise solution of 9B.

  • You need to check both the continuity and differentiability of the given functions in the exercise solution of 9C.

 

Key Features of RS Aggarwal Solutions Class 12 Maths Chapter 9 

Some of the key features of RS Aggarwal Solutions of Class 12 Maths Chapter 9 are listed below.

  • The solutions of Chapter 9 of Class 12 Maths are developed by our subject-matter experts who have years of experience in this field to deliver you complete and precise solutions for all the questions. 

  • The answers are written in a very simple language and step-by-step manner, which will help build strong calculus fundamentals. 

  • Practising these questions will help improve your marks and boost your analytical skills.

  • The solutions are available in free PDF format to download, and you can access this free PDF by clicking on “Download PDF”. 


Exercise-Wise Discussion of RS Aggarwal Solutions for Class 12 Chapter 9 Continuity and Differentiability

  • In the exercise of 9A, you will learn about the conditions required to prove whether a function is continuous or discontinuous by checking the mandatory conditions. 

  • You have to check the continuity of more complex functions in exercise 9B.

  • You need to check both the continuity and differentiability of the given functions in exercise 9C.


Key Features of RS Aggarwal Solutions Class 12 Maths Chapter 9 

Some of the key features of RS Aggarwal Solutions of Class 12 Maths Chapter 9 are listed below.

  • The solutions of Chapter 9 of Class 12 Maths are developed by our subject-matter experts who have years of experience in this field to deliver you complete and precise solutions for all the questions. 

  • The answers are written in a very simple language and step-by-step manner, which will help build strong calculus fundamentals. 

  • Practising these questions will help improve your marks and boost your analytical skills.

  • The solutions are available in free PDF format to download, and you can access this free PDF by clicking on “Download PDF”. 

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FAQs on RS Aggarwal Solutions Class 12 Chapter-9 Continuity and Differentiability

1. Why should I use RS Aggarwal solutions for Class 12 Maths Chapter 9 alongside my NCERT textbook?

RS Aggarwal solutions for Continuity and Differentiability offer a wider variety of problems than the NCERT textbook. They provide extensive practice on complex functions and higher-order thinking skills (HOTS) questions, which is crucial for building a strong foundation for both the CBSE board exams and competitive exams. Using these solutions helps you master different problem-solving approaches and reinforces your conceptual understanding.

2. How are the exercises in RS Aggarwal Class 12 Chapter 9 structured to teach Continuity and Differentiability?

Chapter 9 in the Class 12 RS Aggarwal textbook typically contains multiple exercises, each designed to build your skills progressively. The solutions guide you through these stages:

  • Initial exercises focus on applying the fundamental conditions to prove if a function is continuous or discontinuous at a specific point.
  • Subsequent exercises introduce more complex functions, including trigonometric and modulus functions, to test your understanding of continuity.
  • Later exercises combine both concepts, requiring you to check for both the continuity and differentiability of given functions, reinforcing the relationship between them.

3. What is the step-by-step method shown in these solutions for checking the continuity of a function f(x) at a point x = c?

The solutions demonstrate the correct method as per the CBSE 2025-26 syllabus. To prove a function is continuous at a point x = c, you must show that three conditions are met:

  • The function is defined at x = c, meaning f(c) has a finite value.
  • The limit of the function as x approaches c exists. This is done by proving the Left-Hand Limit (LHL) equals the Right-Hand Limit (RHL): lim(x→c⁻) f(x) = lim(x→c⁺) f(x).
  • The limit of the function at the point equals the function's value at that point: lim(x→c) f(x) = f(c).

The solutions provide detailed calculations for each of these steps for every problem.

4. Do the RS Aggarwal solutions for Chapter 9 cover important theorems like Rolle's Theorem and the Mean Value Theorem?

Yes, the RS Aggarwal solutions provide detailed, step-by-step methods for solving problems based on Rolle’s Theorem and the Lagrange's Mean Value Theorem (LMVT). The solutions clearly explain how to check for the required conditions (continuity on [a, b] and differentiability on (a, b)) and then demonstrate how to find the value 'c' that satisfies the conclusion of the respective theorem.

5. I am struggling to understand the difference between continuity and differentiability. How do the solutions help clarify this?

This is a common point of confusion. The RS Aggarwal solutions help by providing examples that illustrate the key relationship: if a function is differentiable at a point, it must be continuous at that point. However, the converse is not always true. The solutions will guide you through problems involving functions like the modulus function (e.g., |x|) at x=0, which are continuous but not differentiable, thereby clarifying the distinction through practical application.

6. Beyond just getting the final answer, what should I focus on when using the RS Aggarwal solutions for this chapter?

To truly benefit, you should focus on the problem-solving methodology. Pay close attention to:

  • The logical flow of each step, especially in proof-based questions.
  • How different rules of differentiation (like the Chain Rule or Logarithmic Differentiation) are applied to specific types of functions.
  • The precise mathematical notation used, as this is critical for scoring full marks in board exams.

Treat the solutions as a guide to learn the 'how' and 'why', not just as an answer key.

7. What are some common mistakes to avoid when solving problems from Chapter 9, which the solutions can help me identify?

When working through the RS Aggarwal solutions for Continuity and Differentiability, you can learn to avoid common errors such as:

  • Forgetting to check all three conditions for continuity: Many students only check if the Left-Hand Limit equals the Right-Hand Limit but forget to show it equals the value of the function at that point.
  • Incorrectly applying the Chain Rule: Misidentifying the inner and outer functions in a composite function is a frequent mistake.
  • Errors in logarithmic differentiation: Making mistakes while applying properties of logarithms before differentiating.

By comparing your method to the correct, detailed steps in the solutions, you can identify and rectify these mistakes.