Continuity And Differentiability Class 12 Notes Chapter 5

CBSE Class 12 Maths Chapter 5 Notes: Continuity and Differentiability

List of Content
What is a continuous Function?
Chain Rule
Logarithmic Differentiation
What is Rolle’s Theorem?
What is Mean Value Theorem?

Students can refer to the short notes and MCQ questions along with separate solution pdf of this chapter for quick revision from the links below:

What is a Continuous Function?

When in a function, the real value at a point is said to be continuous when at that point, the function of that point is equal to the limit of the function at that point. The continuity exists when all of the domain is continuous.

The difference, product, and quotient are continuous when it comes to a continuous function. Let’s understand with the help of an example.


\(\begin{array}{l}\pm\end{array} \)
\(\begin{array}{l}\pm\end{array} \)
g(x) is said to be continuous.

(f.g)(x)=f(x).g(x) is again said to be continous.

(f/g)(x)=f(x)/g(x) and g(x)

\(\begin{array}{l}\neq\end{array} \)
0 and is said to be continous.

All the functions which are differential are said to be continuous, but vice versa is not true.

Chain Rule

The composite of the functions can be differentiated with the help of chain rule. If f=v, t=u(x)
Then the existence of

\(\begin{array}{l}\frac{\partial t}{\partial x}\end{array} \)
\(\begin{array}{l}\frac{\partial v}{\partial x}\end{array} \)
can be witnessed, then,
\(\begin{array}{l}\frac{\partial f}{\partial x}=\frac{\partial v}{\partial t}.\frac{\partial t}{\partial x}\end{array} \)

Logarithmic Differentiation

When the differential equation is in the form

\(\begin{array}{l}f(x)=[u(x)]^{v(x)}\end{array} \)
. Here, the positive values of f(x) and u(x) is considered.

What is Rolle’s Theorem?

Let us consider a continuous function f:[a,b]

\(\begin{array}{l}\rightarrow\end{array} \)
R, which is continuous on the point [a,b] and differentiable on the point (a,b) then, f(a)=f(b) and some external point exists such as c in (a,b) such that f'(c)=0.

What is Mean Value Theorem?

Let us consider a continuous function f:[a,b]

\(\begin{array}{l}\rightarrow\end{array} \)
R which is continuous on the point [a,b] and differentiable on the point (a,b), some external point exists such as c in (a,b) such that
\(\begin{array}{l}f'(c)=f(b)-f(a)/b-a\end{array} \)


Also Access 
NCERT Solutions for Class 12 Maths Chapter 5
NCERT Exemplar for Class 12 Maths Chapter 5

Important Questions

  1. If
    \(\begin{array}{l}\cos y=x\cos (a+y), with \cos a\neq \pm 1, prove \; that \frac{\partial y}{\partial x}=\cos ^{2}(a+y)/\sin a\end{array} \)
  2. If
    \(\begin{array}{l}x=a(\cos t+t\sin t) and, y=a(\sin t-t\cos t), find \frac{\partial^2 y}{\partial x^2}\end{array} \)
  3. If
    \(\begin{array}{l}f(x)=\left | x \right |^{3}\end{array} \)
    show that f’’(x) is available for the value of x and find it.
  4. With the help of mathematical induction, prove that
    \(\begin{array}{l}\frac{\partial }{\partial x}(x^{n})=nx^{n-1}\end{array} \)
    for integers of n anf positive.
  5. Obtain the same formula as cosines when
    \(\begin{array}{l}\sin (A+B)=\sin A\cos B+\cos A\sin B\end{array} \)

Also, Read

Continuity and Differentiability Limits and Continuity

Frequently Asked Questions on CBSE Class 12 Maths Notes Chapter 5 Continuity and Differentiation


What does the intermediate value theorem state?

In mathematical analysis, the intermediate value theorem states that if f is a continuous function whose domain contains the interval [a, b], then it takes on any given value between f(a) and f(b) at some point within the interval.


What does limit mean in mathematical terms?

In mathematics, a limit is a value that a function (sequence) approaches as the input (or index) approaches some value.


What is a differential equation?

A differential equation is a mathematical equation that involves variables like x or y, as well as the rate at which those variables change.


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