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RD Sharma solutions for Mathematics [English] Class 12 chapter 10 - Differentiability [Latest edition]

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RD Sharma solutions for Mathematics [English] Class 12 chapter 10 - Differentiability - Shaalaa.com
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Solutions for Chapter 10: Differentiability

Below listed, you can find solutions for Chapter 10 of CBSE, Karnataka Board PUC RD Sharma for Mathematics [English] Class 12.


Exercise 10.1Exercise 10.2Exercise 10.3Exercise 10.4
Exercise 10.1 [Pages 10 - 11]

RD Sharma solutions for Mathematics [English] Class 12 10 Differentiability Exercise 10.1 [Pages 10 - 11]

Exercise 10.1 | Q 1 | Page 10

Show that f(x) = |x − 2| is continuous but not differentiable at x = 2. 

Exercise 10.1 | Q 2 | Page 10

Show that f(x) = x1/3 is not differentiable at x = 0.

Exercise 10.1 | Q 3 | Page 10

Show that \[f\left( x \right) =\]`{(12x, -,13, if , x≤3),(2x^2, +,5, if x,>3):}` is differentiable at x = 3. Also, find f'(3).

Exercise 10.1 | Q 4 | Page 10

Show that the function f defined as follows, is continuous at x = 2, but not differentiable thereat: 

\[f\left( x \right) = \begin{cases}3x - 2, & 0 < x \leq 1 \\ 2 x^2 - x, & 1 < x \leq 2 \\ 5x - 4, & x > 2\end{cases}\]
Exercise 10.1 | Q 5 | Page 10

Discuss the continuity and differentiability of the 

\[f\left( x \right) = \left| x \right| + \left| x - 1 \right| \text{in the interval} \left( - 1, 2 \right)\]
Exercise 10.1 | Q 6 | Page 10

Find whether the function is differentiable at x = 1 and x = 2 

\[f\left( x \right) = \begin{cases}x & x \leq 1 \\ \begin{array} 22 - x  \\ - 2 + 3x - x^2\end{array} & \begin{array}11 \leq x \leq 2 \\ x > 2\end{array}\end{cases}\]
Exercise 10.1 | Q 7 | Page 10

Show that the function 

\[f\left( x \right) = \begin{cases}x^m \sin\left( \frac{1}{x} \right) & , x \neq 0 \\ 0 & , x = 0\end{cases}\]

(i) differentiable at x = 0, if m > 1
(ii) continuous but not differentiable at x = 0, if 0 < m < 1
(iii) neither continuous nor differentiable, if m ≤ 0

Exercise 10.1 | Q 8 | Page 10

Find the values of a and b so that the function

\[f\left( x \right)\begin{cases}x^2 + 3x + a, & \text { if } x \leq 1 \\ bx + 2 , &\text {  if } x > 1\end{cases}\] is differentiable at each x ∈ R.
Exercise 10.1 | Q 9 | Page 10

Show that the function 

\[f\left( x \right) = \begin{cases}\left| 2x - 3 \right| \left[ x \right], & x \geq 1 \\ \sin \left( \frac{\pi x}{2} \right), & x < 1\end{cases}\] is continuous but not differentiable at x = 1.

Exercise 10.1 | Q 10 | Page 11

If \[f\left( x \right) = \begin{cases}a x^2 - b, & \text { if }\left| x \right| < 1 \\ \frac{1}{\left| x \right|} , & \text { if }\left| x \right| \geq 1\end{cases}\]  is differentiable at x = 1, find a, b.

Exercise 10.1 | Q 11 | Page 11

Find the values of a and b, if the function f defined by 

\[f\left( x \right) = \begin{cases}x^2 + 3x + a & , & x \leqslant 1 \\ bx + 2 & , & x > 1\end{cases}\] is differentiable at = 1.
Exercise 10.2 [Page 16]

RD Sharma solutions for Mathematics [English] Class 12 10 Differentiability Exercise 10.2 [Page 16]

Exercise 10.2 | Q 1 | Page 16

If f is defined by f (x) = x2, find f'(2).

Exercise 10.2 | Q 2 | Page 16

If is defined by  \[f\left( x \right) = x^2 - 4x + 7\] , show that \[f'\left( 5 \right) = 2f'\left( \frac{7}{2} \right)\] 

Exercise 10.2 | Q 3 | Page 16

Show that the derivative of the function f given by 

\[f\left( x \right) = 2 x^3 - 9 x^2 + 12x + 9\], at x = 1 and x = 2 are equal.
Exercise 10.2 | Q 4 | Page 16

If for the function 

\[\Phi \left( x \right) = \lambda x^2 + 7x - 4, \Phi'\left( 5 \right) = 97, \text { find } \lambda .\]

Exercise 10.2 | Q 5 | Page 16

If  \[f\left( x \right) = x^3 + 7 x^2 + 8x - 9\] 

, find f'(4).

Exercise 10.2 | Q 6 | Page 16

Find the derivative of the function f defined by f (x) = mx + c at x = 0.

Exercise 10.2 | Q 7 | Page 16

Examine the differentialibilty of the function f defined by

\[f\left( x \right) = \begin{cases}2x + 3 & \text { if }- 3 \leq x \leq - 2 \\ \begin{array}xx + 1 \\ x + 2\end{array} & \begin{array} i\text { if } - 2 \leq x < 0 \\\text {  if } 0 \leq x \leq 1\end{array}\end{cases}\] 

Exercise 10.2 | Q 8 | Page 16

Write an example of a function which is everywhere continuous but fails to differentiable exactly at five points.

Exercise 10.2 | Q 9 | Page 16

Discuss the continuity and differentiability of f (x) = |log |x||.

Exercise 10.2 | Q 10 | Page 16

Discuss the continuity and differentiability of f (x) = e|x| .

Exercise 10.2 | Q 11 | Page 16

Discuss the continuity and differentiability of 

\[f\left( x \right) = \begin{cases}\left( x - c \right) \cos \left( \frac{1}{x - c} \right), & x \neq c \\ 0 , & x = c\end{cases}\]
Exercise 10.2 | Q 12 | Page 16

Is |sin x| differentiable? What about cos |x|?

Exercise 10.3 [Page 17]

RD Sharma solutions for Mathematics [English] Class 12 10 Differentiability Exercise 10.3 [Page 17]

Exercise 10.3 | Q 1 | Page 17

Define differentiability of a function at a point.

 
Exercise 10.3 | Q 2 | Page 17

Is every differentiable function continuous?

Exercise 10.3 | Q 3 | Page 17

Is every continuous function differentiable?

Exercise 10.3 | Q 4 | Page 17

Give an example of a function which is continuos but not differentiable at at a point.

Exercise 10.3 | Q 5 | Page 17

If f (x) is differentiable at x = c, then write the value of 

\[\lim_{x \to c} f \left( x \right)\]
Exercise 10.3 | Q 6 | Page 17

If f (x) = |x − 2| write whether f' (2) exists or not.

Exercise 10.3 | Q 7 | Page 17

Write the points where f (x) = |loge x| is not differentiable.

Exercise 10.3 | Q 8 | Page 17

Write the points of non-differentiability of 

\[f \left( x \right) = \left| \log \left| x \right| \right| .\]
Exercise 10.3 | Q 9 | Page 17

Write the derivative of f (x) = |x|3 at x = 0.

Exercise 10.3 | Q 10 | Page 17

Write the number of points where f (x) = |x| + |x − 1| is continuous but not differentiable.

Exercise 10.3 | Q 11 | Page 17

If  \[\lim_{x \to c} \frac{f\left( x \right) - f\left( c \right)}{x - c}\]  exists finitely, write the value of  \[\lim_{x \to c} f\left( x \right)\]

Exercise 10.3 | Q 12 | Page 17

Write the value of the derivative of f (x) = |x − 1| + |x − 3| at x = 2.

Exercise 10.3 | Q 13 | Page 17

If  \[f \left( x \right) = \sqrt{x^2 + 9}\] , write the value of

\[\lim_{x \to 4} \frac{f\left( x \right) - f\left( 4 \right)}{x - 4} .\]
Exercise 10.4 [Pages 17 - 20]

RD Sharma solutions for Mathematics [English] Class 12 10 Differentiability Exercise 10.4 [Pages 17 - 20]

Exercise 10.4 | Q 1 | Page 17

Let f (x) = |x| and g (x) = |x3|, then

  •  f (x) and g (x) both are continuous at x = 0

  • f (x) and g (x) both are differentiable at x = 0

  • f (x) is differentiable but g (x) is not differentiable at x = 0

  •  f (x) and g (x) both are not differentiable at x = 0

Exercise 10.4 | Q 2 | Page 17

The function f (x) = sin−1 (cos x) is

  • discontinuous at x = 0

  • continuous at x = 0

  • differentiable at x = 0

  • none of these

Exercise 10.4 | Q 3 | Page 17

The set of points where the function f (x) = x |x| is differentiable is 

 

  • \[\left( - \infty , \infty \right)\]

  • \[\left( - \infty , 0 \right) \cup \left( 0, \infty \right)\]

  • \[\left( 0, \infty \right)\]

  • \[\left[ 0, \infty \right]\]

Exercise 10.4 | Q 4 | Page 17

If \[f\left( x \right) = \begin{cases}\frac{\left| x + 2 \right|}{\tan^{- 1} \left( x + 2 \right)} & , x \neq - 2 \\ 2 & , x = - 2\end{cases}\]  then f (x) is

  • continuous at x = − 2

  • not continuous at x = − 2

  • differentiable at x = − 2

  • continuous but not derivable at x = − 2

Exercise 10.4 | Q 5 | Page 18

Let \[f\left( x \right) = \left( x + \left| x \right| \right) \left| x \right|\]

  • f is continuous

  •  f is differentiable for some x

  • f' is continuous

  • f'' is continuous

Exercise 10.4 | Q 6 | Page 18

The function f (x) = e|x| is

  • continuous everywhere but not differentiable at x = 0

  • continuous and differentiable everywhere

  • not continuous at x = 0

  • none of these

Exercise 10.4 | Q 7 | Page 18

The function f (x) = |cos x| is

  • everywhere continuous and differentiable

  • everywhere continuous but not differentiable at (2n + 1) π/2, n ∈ Z

  • neither continuous nor differentiable at (2n + 1) π/2, n ∈ Z

  • none of these

Exercise 10.4 | Q 8 | Page 18

If \[f\left( x \right) = \sqrt{1 - \sqrt{1 - x^2}},\text{ then } f \left( x \right)\text {  is }\] 

  • continuous on [−1, 1] and differentiable on (−1, 1)

  • continuous on [−1, 1] and differentiable on
    \[\left( - 1, 0 \right) \cup \left( 0, 1 \right)\]

  • continuous and differentiable on [−1, 1]

  • none of these

Exercise 10.4 | Q 9 | Page 18

If \[f\left( x \right) = a\left| \sin x \right| + b e^\left| x \right| + c \left| x \right|^3\] 

  • \[a = b = c = 0\]

  • \[a = 0, b = 0; c \in R\]

     

  • \[b = c = 0, a \in R\]

  • \[c = 0, a = 0, b \in R\]

     

Exercise 10.4 | Q 10 | Page 18

If \[f\left( x \right) = x^2 + \frac{x^2}{1 + x^2} + \frac{x^2}{\left( 1 + x^2 \right)} + . . . + \frac{x^2}{\left( 1 + x^2 \right)} + . . . . ,\] 

then at x = 0, f (x)

  • has no limit

  • is discontinuous

  • is continuous but not differentiable

  • is differentiable

Exercise 10.4 | Q 11 | Page 18

If \[f\left( x \right) = \left| \log_e x \right|, \text { then}\]

  • \[f' \left( 1^+ \right) = 1\]

  • \[f' \left( 1 \right) = - 1\]

  • \[f' \left( 1 \right) = 1\]

  • \[f' \left( 1 \right) = - 1\]

Exercise 10.4 | Q 12 | Page 18

If \[f\left( x \right) = \left| \log_e |x| \right|\] 

  • f (x) is continuous and differentiable for all x in its domain

  • f (x) is continuous for all for all × in its domain but not differentiable at x = ± 1

  •  (x) is neither continuous nor differentiable at x = ± 1

  • none of these

     

Exercise 10.4 | Q 13 | Page 18

Let \[f\left( x \right) = \begin{cases}\frac{1}{\left| x \right|} & for \left| x \right| \geq 1 \\ a x^2 + b & for \left| x \right| < 1\end{cases}\] If f (x) is continuous and differentiable at any point, then

 

 

 

  • \[a = \frac{1}{2}, b = - \frac{3}{2}\]

  • \[a = - \frac{1}{2}, b = \frac{3}{2}\]

  • a = 1, b = − 1

  • none of these

Exercise 10.4 | Q 14 | Page 18

The function f (x) = x − [x], where [⋅] denotes the greatest integer function is

  • continuous everywhere

  • continuous at integer points only

  • continuous at non-integer points only

  • differentiable everywhere

Exercise 10.4 | Q 15 | Page 18

Let \[f\left( x \right)\begin{cases}a x^2 + 1, & x > 1 \\ x + 1/2, & x \leq 1\end{cases}\] . Then, f (x) is derivable at x = 1, if 

  • a = 2

  • a = 1

  • a = 0

  • a = 1/2

Exercise 10.4 | Q 16 | Page 19

Let f (x) = |sin x|. Then,

  • f (x) is everywhere differentiable.

  • f (x) is everywhere continuous but not differentiable at x = n π, n ∈ Z

  • f (x) is everywhere continuous but not differentiable at  \[x = \left( 2n + 1 \right)\frac{\pi}{2}, n \in Z\]

  • none of these

Exercise 10.4 | Q 17 | Page 19

Let f (x) = |cos x|. Then,

  • f (x) is everywhere differentable

  •  f (x) is everywhere continuous but not differentiable at x = n π, n ∈ Z

  • f (x) is everywhere continuous but not differentiable at \[x = \left( 2n + 1 \right)\frac{\pi}{2}, n \in Z\].

  • (d) none of these

Exercise 10.4 | Q 18 | Page 19

The function f (x) = 1 + |cos x| is

  • continuous no where

  • continuous everywhere

  •  not differentiable at x = 0

  • not differentiable at x = n π, n ∈ Z

Exercise 10.4 | Q 19 | Page 19

The function f (x) =  |cos x| is

  • differentiable at x = (2n + 1) π/2, n ∈ Z

  •  continuous but not differentiable at x = (2n + 1) π/2, n ∈ Z

  • neither differentiable nor continuous at x = n ∈ Z

  •  none of these

Exercise 10.4 | Q 20 | Page 19

The function \[f\left( x \right) = \frac{\sin \left( \pi\left[ x - \pi \right] \right)}{4 + \left[ x \right]^2}\] , where [⋅] denotes the greatest integer function, is

  • continuous as well as differentiable for all x ∈ R

  • continuous for all x but not differentiable at some x

  • differentiable for all x but not continuous at some x.

  • none of these

Exercise 10.4 | Q 21 | Page 19

Let f (x) = a + b |x| + c |x|4, where a, b, and c are real constants. Then, f (x) is differentiable at x = 0, if

  • a = 0

  • b = 0

  • c = 0

  • none of these

Exercise 10.4 | Q 22 | Page 19

If f (x) = |3 − x| + (3 + x), where (x) denotes the least integer greater than or equal to x, then f (x) is

  • continuous and differentiable at x = 3

  • continuous but not differentiable at x = 3

  • differentiable nut not continuous at x = 3

  • neither differentiable nor continuous at x = 3

Exercise 10.4 | Q 23 | Page 19

If \[f\left( x \right) = \begin{cases}\frac{1}{1 + e^{1/x}} & , x \neq 0 \\ 0 & , x = 0\end{cases}\]  then f (x) is 

  • continuous as well as differentiable at x = 0

  • continuous but not differentiable at x = 0

  • differentiable but not continuous at x = 0

  • none of these

Exercise 10.4 | Q 24 | Page 19

If \[f\left( x \right) = \begin{cases}\frac{1 - \cos x}{x \sin x}, & x \neq 0 \\ \frac{1}{2} , & x = 0\end{cases}\] 

then at x = 0, f (x) is

  • continuous and differentiable

  • differentiable but not continuous

  • continuous but not differentiable

  • neither continuous nor differentiable

Exercise 10.4 | Q 25 | Page 20

The set of points where the function f (x) given by f (x) = |x − 3| cos x is differentiable, is

  • R

  • R − {3}

  • (0, ∞)

  • none of these

Exercise 10.4 | Q 26 | Page 20

Let \[f\left( x \right) = \begin{cases}1 , & x \leq - 1 \\ \left| x \right|, & - 1 < x < 1 \\ 0 , & x \geq 1\end{cases}\] Then, f is 

  • continuous at x = − 1

  • differentiable at x = − 1

  • everywhere continuous

  • everywhere differentiable

Solutions for 10: Differentiability

Exercise 10.1Exercise 10.2Exercise 10.3Exercise 10.4
RD Sharma solutions for Mathematics [English] Class 12 chapter 10 - Differentiability - Shaalaa.com

RD Sharma solutions for Mathematics [English] Class 12 chapter 10 - Differentiability

Shaalaa.com has the CBSE, Karnataka Board PUC Mathematics Mathematics [English] Class 12 CBSE, Karnataka Board PUC solutions in a manner that help students grasp basic concepts better and faster. The detailed, step-by-step solutions will help you understand the concepts better and clarify any confusion. RD Sharma solutions for Mathematics Mathematics [English] Class 12 CBSE, Karnataka Board PUC 10 (Differentiability) include all questions with answers and detailed explanations. This will clear students' doubts about questions and improve their application skills while preparing for board exams.

Further, we at Shaalaa.com provide such solutions so students can prepare for written exams. RD Sharma textbook solutions can be a core help for self-study and provide excellent self-help guidance for students.

Concepts covered in Mathematics [English] Class 12 chapter 10 Differentiability are Algebra of Continuous Functions, Concept of Differentiability, Derivatives of Composite Functions - Chain Rule, Concept of Continuity, Derivatives of Implicit Functions, Derivatives of Inverse Trigonometric Functions, Exponential and Logarithmic Functions, Logarithmic Differentiation, Derivatives of Functions in Parametric Forms, Second Order Derivative, Derivative - Exponential and Log, Proof Derivative X^n Sin Cos Tan, Infinite Series, Higher Order Derivative, Continuous Function of Point, Mean Value Theorem.

Using RD Sharma Mathematics [English] Class 12 solutions Differentiability exercise by students is an easy way to prepare for the exams, as they involve solutions arranged chapter-wise and also page-wise. The questions involved in RD Sharma Solutions are essential questions that can be asked in the final exam. Maximum CBSE, Karnataka Board PUC Mathematics [English] Class 12 students prefer RD Sharma Textbook Solutions to score more in exams.

Get the free view of Chapter 10, Differentiability Mathematics [English] Class 12 additional questions for Mathematics Mathematics [English] Class 12 CBSE, Karnataka Board PUC, and you can use Shaalaa.com to keep it handy for your exam preparation.

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