Continuity and Differentiability Class 12 Mathematics Exam Questions

Exam Questions Class 12

Please refer to Continuity and Differentiability Class 12 Mathematics Exam Questions provided below. These questions and answers for Class 12 Mathematics have been designed based on the past trend of questions and important topics in your Class 12 Mathematics books. You should go through all Class 12 Mathematics Important Questions provided by our teachers which will help you to get more marks in upcoming exams.

Class 12 Mathematics Exam Questions Continuity and Differentiability

Class 12 Mathematics students should read and understand the important questions and answers provided below for Continuity and Differentiability which will help them to understand all important and difficult topics.

Very Short Answer Type Questions

Question. Write the derivative of sin x w.r.t. cos x.
Answer. Let y = sin x ; Let z = cos x

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If the following function f (x) is continuous at x = 0, then write the value of k

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Short Answer Type Questions-I

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. sin2 y + cos xy = K
Differentiating both sides w.r.t. x, we have

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the value of k for which the function f(x)

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the value of p for which the function f (x)

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. f (x) = sin 2x – cos 2x
Differentiating both sides w.r.t. x, we get
f«(x) = 2 cos 2x + 2 sin 2x

Continuity and Differentiability Class 12 Mathematics Exam Questions

Short Answer Type Questions-II

Question. Differentiate the following function w.r.t. x ; xsin x + (sin x)cos x
Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. (x2 + y2)2 = xy
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the value of ‘a’ for which the function f defined as

Continuity and Differentiability Class 12 Mathematics Important Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Important Questions
Continuity and Differentiability Class 12 Mathematics Important Questions

Question. Find the values of a and b such that the following function f (x) is a continuous function :

Continuity and Differentiability Class 12 Mathematics Important Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Since f(x) is continuous.
∴ L.H.L. = R.H.L. = f (10)
10a + b = 21 = 21
10a + b = 21
10a + 5 – 2a = 21 [From (i)
8a = 21 – 5 = 16
∴ a = 2
Putting the value of a in (i), we get
b = 5 – 2(2) = 5 – 4 = 1
∴ a = 2, b = 1

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. sin y = x sin (a + y)

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If (cos x)= (sin y)x, find dy/dx
Answer.
(cos x)y = (sin y)x
Taking log on both sides, we get
∴ log (cos x) = x log (sin y)
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. y = ex(sin x + cos x) …(i)
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Show that the function f (x) defined by f (x)

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If y = (log x)x + (x)cos x, find dy/dx
Answer.
y = (log x)x + (x)cos x
Let y = A + B

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find all points of discontinuity of f, where f is defined as follows :

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. Case I : At x = – 3

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If x = 2 cos θ – cos 2θ and y = 2 sin θ – sin 2θ, then prove that

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If y = (sin x)x + sin–1 √x , then find.
Answer. Let A = (sin x)x
Taking log on both sides,
log A = x log sin x
Differentiating both sides w.r.t. x, we have

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. For what value of k is the function defined by

Continuity and Differentiability Class 12 Mathematics Exam Questions

continuous at x = 0? Also write whether the function is continuous at x = 1.
Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the values of a and b such that the function defined as follows is continuous :

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If x = cos θ and y = sin3 θ, then prove that

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the value of the constant k so that the function f, defined below, is continuous at x = 0, where

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find the value of k, for which the function f defined below is continuous :

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. If the function f (x), defined as

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

f (x) is continuous at x = 1
∴ L.H.L. = R.H.L. = f (1)
5a – 2b = 3a + b = 11
3a + b = 11             ⇒ b = 11 – 3a …(i)
5a – 2b = 11
5a – 2(11 – 3a) = 11                   [From (i)]
5a – 22 + 6a = 11
11a = 33                  ⇒ a = 3
Putting the value of a in (i), we get
b = 11 – 3(3) = 11 – 9 = 2        ∴ a = 3, b = 2

Question. If the function

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

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

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. (i) For continuity at x = 2

Continuity and Differentiability Class 12 Mathematics Exam Questions
Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. y = xx (Given)
Taking log on both sides
log y = log xx
log y = x log x
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question. Find dy/dx , if y = (cos x)x + (sin x)1/x
Answer. 
y = (cos x)x + (sin x)1/x

Continuity and Differentiability Class 12 Mathematics Exam Questions

A= (cos x)x
Taking log on both sides
log A = x (log cos x)
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. y = ea sin−1 …(i)
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. y = (cot–1 x)2
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions

Question.

Continuity and Differentiability Class 12 Mathematics Exam Questions

Answer. y = (sin x – cos x)(sin x – cos x)
Taking log on both sides, we get
log y = (sin x – cos x).log(sin x – cos x)
Differentiating both sides w.r.t. x, we get

Continuity and Differentiability Class 12 Mathematics Exam Questions


CASE STUDY :

P(x) = -5x2 +125x + 37500 is the total profit function of a company, where x is the production of the company.

Question. What will be the production when the profit is maximum?
a. 37500
b. 12.5
c. -12.5
d. –37500

Answer

B

Question. What will be the maximum profit?
a. Rs 38,28,125
b. Rs 38281.25
c. Rs 39,000
d. None

Answer

B

Question. Check in which interval the profit is strictly increasing .
a. (12.5,∞ )
b. for all real numbers
c. for all positive real numbers
d. (0, 12.5)

Answer

D

Question. When the production is 2units what will be the profit of the company?
a. 37500
b. 37,730
c. 37,770
d. None

Answer

B

Question. What will be production of the company when the profit is Rs 38250?
a. 15
b. 30
c. 2
d. data is not sufficient to find

Answer

A

CASE STUDY :

Continuity and Differentiability Class 12 Mathematics Exam Questions

The bridge connects two hills 100 feet apart. The arch on the bridge is in a parabolic form.
The highest point on the bridge is 10 feet above the road at the middle of the bridge as seen in the figure.
Based on the information given above, answer the following questions:

Question. The equation of the parabola designed on the bridge is
a. 𝑥2 = 250𝑦
b. 𝑥2 = −250𝑦
c. 𝑦2 = 250𝑥
d. 𝑦2 = 250𝑦

Answer

B

Question. The value of the integral

Continuity and Differentiability Class 12 Mathematics Exam Questions

is
a. 1000/3
b. 250/3
c. 1200
d. 0

Answer

A

Question. The integrand of the integral 

Continuity and Differentiability Class 12 Mathematics Exam Questions

is _________ function.
a. Even
b. Odd
c. Neither odd nor even
d. None

Answer

A

Question. The area formed by the curve x2= 250y , x-axis , y = 0 and y = 10 is
a. 1000 √2/3
b. 4/3
c. 1000/3
d. 0

Answer

C

Question. The area formed between x2 = 250y , y-axis , y = 2 and y = 4 is
a. 1000/3
b. 0
c. 1000 √2/3
d. none of these

Answer

D