Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Let f(x) = { x2 , when 0 ≤ x ≤ 2. 2x, when 2 ≤ x ≤ 5.g(x) = { x2 , when 0 ≤ x ≤ 3. 2x, when 3 ≤ x ≤ 5. Show that f is a function while g is not a function.

Answer»

The relation is defined as

f (x) = { x2 , when 0 ≤ x ≤ 3 

            2x, when 3 ≤ x ≤ 5 

It is observed that for 

0 ≤ x ≤ 2, f(x) = x2 And 2 ≤ x ≤ 5, f(x) = 2x 

Also, at x = 2, f (x) = 22 = 4 or f(x) = 2 × 2 = 4 

i,e at x = 2, f(x) = 4. 

Therefore, for 0≤ x ≤ 5, the image of f (x) are unique Thus, the given relation ‘f’ is a function. The relation g is defined as g(x) = { x2 , when 0 ≤ x ≤ 3 2, when 3 ≤ x ≤ 5 It can be observed that for x = 3 g(x) = 32 = 9 and g (x) = 2 × 3 = 6 Hence, element 3 of the domain of relation ‘g’ corresponds to two different images i.e., 9 and 6. Hence, this relation is not a function.

2.

Define a relation R on the set N of natural numbers by R = {(x, y): y = 2x - 1; x, y ∈ N, x ≤ 5}. Depict this relationship using roster form, Write down the domain and range.

Answer»

Given y = 2x – 1 and x ≤ 5 

for x = 1, y = 2 × 1 – 1 = 1 

x = 2, y = 2 × 2 – 1 = 3 

x = 3, y = 2 × 3 – 1 = 5 

x = 4, y = 2 × 4 – 1 = 7 

x = 5, y = 2 × 5 – 1 = 9 

Relation R = {(1, 1), (2, 3), (3, 5), (4, 7), (5, 9)} 

∴ Domain = {1, 2, 3, 4, 5} 

∴ Range = {1, 3, 5, 7, 9}

3.

Define Liver and its main function?

Answer»

Liver is the largest solid organ in the body situated in the upper part of the abdomen on the right side. The main function of liver is to filter the blood coming from the digestive tract, before passing it to the rest of the body.

4.

What is the role of gall bladder?

Answer»

The excess bile secreted by the Liver is stored in the gall bladder.

5.

Observe the illustration and write down the questions below.1. What is the role of uvula? 2 compresses the food into balls with the help of plate? 3. State whether true or false? The trachea tilts up and it is closed by the epiglottis

Answer»

1. Uvula doses the nasal cavity that opens to the pharynx 

2. Tongue 

3. True

6.

The Cartesian product A x A has 9 elements along which are found (-1, 0) and (0,1). Find the set A and the remaining elements A x A.

Answer»

Given n(A x A) = 9 = 32

⇒n(A) = 3

But (-1, 0) and (0, 1) are in A x A

∴ A= {-1,0,1}.

Remaining elements of A x A: (-1, -1), (-1, 1),

(0,-1), (0,0), (1,-1), (1,0), (1,1).

7.

If there are 28 relation from a set A = {2,4, 6, 8} to a set B, then the number of elements in B is …(1) 7(2) 14(3) 5(4) 4

Answer»

(1) 7

n(A) = 4

n(A x B) = 28

n(A) x n(B) = 28

4 x n(B) = 28

n(B) = 28/4 = 7

8.

Let A and B be two sets such that n(A) = 3 and n(B) = 2. If (x, 1) (y, 2), (z, 1) are in A x B, find A and B, where x, y, z are distinct elements.

Answer»

A = {x, y, z} and B = {1, 2}.

9.

Who was the writer of ‘Vruksha Ayurveda’?

Answer»

Maharshi Parashar was the writer of ‘Vruksha Ayurveda’.

10.

Who introduced the types of equation?

Answer»

Brahmgupta introduced the type of equations.

11.

How many chambers are there in the stomach of ruminants? What are those?

Answer»

Ruminants have four chambers in stomach. They are rumen, reticulum, omasum and abomasum.

12.

Who wrote ‘Yogashastra’?

Answer»

Maharashi Patanjali wrote ‘Yogashastra’.

13.

Who wrote ‘Kamsutra’?

Answer»

Vastsayana wrote ‘Kamsutra’.

14.

Who wrote ‘Chikitsa Sangraha’?

Answer»

Chakrapanidatta wrote ‘Chikitsa Sangraph’.

15.

Who wrote ‘Prajananshastra’?

Answer»

Brahmgupta Panchal wrote ‘Prajanan-shastra’.

16.

If P = {1, 3}, Q = {2, 3, 5}, find the number of relations from P to Q

Answer»

Given, P = {1,3} and Q = {2, 3, 5} 

∵ n(P) = 2 and n(Q) = 3 

∴ Number of relations = 2n(p) x n(Q)

= 22 × 3

= \(2^6\)

= 64

17.

If R = {x, y}: x, y ∈ z, x2 + y2 = 64}, then, write R in roster form.

Answer»

    Given, R = {x,y}: x, y ∈ z , x2 + y2 = 64} 

∵ x 2+ y2 = 64 ⇒ y2 = 64 – x 

    ∴  R = {(0, 8), (0, - 8), (8, 0), (- 8, 0)

18.

Define a relation.

Answer»

A relation R from a non-empty set A to non empty set B is a subset of the Cartesian product A x B.

19.

The radii of two circles are 8 cm and 6 cm respectively. Find the radius of the circle having its are equal to the sum of the areas of two circles.

Answer»

Radius of circles are 8cm and 6cm

Area of circle with radius 8cm = π(8)2=64πcm2

Area of circle with radius 6cm = π(6)2=36π cm2

Areas sum = 64π + 36π = 100π cm2

Radius of circle be x cm

Area = πx2

πx2 = 100π

x2=100

⇒x=√100=10cm

20.

Write the value of sin–1(1550°).

Answer»

Given sin-1 (sin 1550°)

= sin-1 (sin (1440° + 110°))

= sin-1 (sin (360° × 4 + 110°))

We know that sin (2nπ + θ) = sin θ

= sin-1 (sin 110°)

We know that sin-1 (sin θ) = π – θ, if θ ∈ [π/2, 3π/2]

= 180° - 110°

= 70°

∴ sin-1 (sin 1550°) = 70°

21.

Write the value of cos–1(cos 1540°).

Answer»

Given cos-1 (cos 1540°)

= cos-1{cos (1440° + 100°)}

= cos -1{cos (360° × 4 + 100°)}

We know that cos (2π + θ) = cos θ

= cos -1{cos 100°}

We know that cos-1 (cos θ) = θ if θ ∈ [0, π]

= 100°

∴ cos-1 (cos 1540°) = 100°

22.

Write the value of sin–1 (sin(–600°)).

Answer»

Given sin-1 (sin (-600°))

= sin -1 (sin (-600 + 360 × 2))

We know that sin (2nπ + θ) = sin θ

= sin (sin 120°)

We know that sin-1 (sin θ) = π – θ, if θ ∈ [π/2, 3π/2]

= 180° - 120° = 60°

∴ sin -1 (sin (-600°)) = 60°

23.

Solve for x and y: 9/x - 4/y = 8, 13/x + 7/y = 101

Answer»

The given equations are: 

9/x - 4/y  = 8 ……..(i) 

13/x + 7/y = 101 ……..(ii) 

Putting 1/x = u and 1/y = v, we get: 

9u - 4v = 8 …….(iii) 

13u + 7v = 101 ……(iv) 

On multiplying (iii) by 7 and (iv) by 4, we get: 

63u - 28v = 56 ……..(v) 

52u + 28v = 404 ……..(vi) 

On adding (v) from (vi), we get: 

115u = 460 

⇒ u = 4 

⇒ 1/ x = 4 

⇒ x = 1/4 

On substituting x = 1/ 4 in (i), we get: 

9/ 1/ 4 - 4/ y = 8 

⇒36 - 4/ y = 8 

⇒ 4/ y = (36 – 8) = 28 

y = 4/ 28 = 1/7 

Hence, the required solution is x = 1/4 and y = 1/ 7.

24.

Solve for x and y:\(\frac{5}x-\frac{3}y=1\),\(\frac{3}{2x}+\frac{2}{3y}=5\)

Answer»

The given equations are:

 \(\frac{5}x-\frac{3}y=1\)..........(i)

\(\frac{3}{2x}+\frac{2}{3y}=5\).......(ii)

Putting 1/x = u and 1/y = v, we get: 

5u - 3v = 1 …….(iii) 

⇒ 3/2 u + 2/3 v = 5

⇒ \(\frac{9u+4v}6\) = 5

⇒ 9u + 4v = 30 …….(iv) 

On multiplying (iii) by 4 and (iv) by 3, we get: 

20u - 12v = 4 ……..(v) 

27u + 12v = 90 ……..(vi) 

On adding (iv) and (v), we get: 

47u = 94 ⇒ u = 2 

⇒ 1/x = 2 ⇒ x = 1/2 

On substituting x = 1/2 in (i), we get:

\(\frac{\frac{5}1}2\) - \(\frac{3}y\) = 1

⇒ 10 - 3/y = 1 ⇒ 3/y = (10 – 1) = 9 

y = 3/9 = 1/3 

Hence, the required solution is x = 1/2 and y = 1/3 .

25.

Solve for x and y:\(\frac{9}x-\frac{4}y=8\),\(\frac{13}x+\frac{7}y=101 \)

Answer»

The given equations are:

 \(\frac{9}x-\frac{4}y=8\)........(i)

\(\frac{13}x+\frac{7}y=101 \).......(ii)

Putting 1/x = u and 1/y = v, we get: 

9u - 4v = 8 …….(iii) 

13u + 7v = 101 ……(iv) 

On multiplying (iii) by 7 and (iv) by 4, we get: 

63u - 28v = 56 ……..(v) 

52u + 28v = 404 ……..(vi) 

On adding (v) from (vi), we get: 

115u = 460 ⇒ u = 4 

⇒ 1/x = 4 ⇒ x = 1/4 

On substituting x = 1 4 in (i), we get:

\(\frac{9}{\frac{1}{4}}\) - 4/y = 8 

⇒ 36 - 4/y = 8 

⇒ 4/y = (36 – 8) = 28 

y = 4/28 = 1/7 

Hence, the required solution is x = 1/4 and y = 1/7.

26.

Solve for x and y:\(\frac{5}{x+y}-\frac{2}{x-y}=-1\),\(\frac{15}{x+y}-\frac{7}{x-y}=10\)

Answer»

The given equations are

 \(\frac{5}{x+y}-\frac{2}{x-y}=-1\).......(i)

\(\frac{15}{x+y}-\frac{7}{x-y}=10\)......(ii)

Substituting 1/x+y = u and 1/x−y = v in (i) and (ii), we get 

5u – 2v = -1 ……..(iii) 

15u + 7v = 10 …….(iv) 

Multiplying (iii) by 3 and subtracting it from (iv), we get 

7v + 6v = 10 + 3 

⇒ 13v = 13 

⇒ v = 1

⇒x – y = 1 \((∵\frac{1}{x-y}=v)\)......(v)

Now, substituting v = 1 in (iii), we get 

5u – 2 = -1 

⇒5u = 1 

⇒u = 1/5 

x + y = 5 …….(vi) 

Adding (v) and (vi), we get 

2x = 6 ⇒ x = 3 

Substituting x = 3 in (vi), we have 

3 + y = 5 ⇒ y = 5 – 3 = 2 

Hence, x = 3 and y = 2.

27.

Solve for x and y:\(\frac{44}{x+y}+\frac{30}{x-y}=10\),\(\frac{55}{x+y}-\frac{40}{x-y}=13\)

Answer»

The given equations are

 \(\frac{44}{x+y}+\frac{30}{x-y}=10\)............(i)

\(\frac{55}{x+y}-\frac{40}{x-y}=13\)..........(ii)

Putting 1/x+y = u and 1/x−y = v, we get: 

44u + 30v = 10 ……..(iii) 

55u + 40v = 13 …….(iv) 

On multiplying (iii) by 4 and (iv) by 3, we get: 

176u + 120v = 40 …..(v) 

165u + 120v = 39 …..(vi) 

On subtracting (vi) and (v), we get: 

11u = 1 

⇒u = 1/11 

⇒ 1/x+y = 1/11 ⇒ x + y = 11 …….(vii) 

On substituting u = 1/11 in (iii), we get: 

4 + 30v = 10 

⇒30v = 6 

⇒v = 6/30 = 1/5 

⇒ 1/x−y = 1/5 ⇒ x – y = 5 …….(viii) 

On adding (vii) and (viii), we get 

2x = 16 

⇒ x = 8 

On substituting x =8 in (vii), we get: 

8 + y = 11 

⇒ y = 11 – 8 = 3 

Hence, the required solution is x = 8 and y = 3.

28.

Solve for x and y:\(\frac{3}{x+y}+\frac{2}{x-y}=2\),\(\frac{9}{x+y}+\frac{4}{x-y}=1\)

Answer»

The given equations are

 \(\frac{3}{x+y}+\frac{2}{x-y}=2\)....(i)

\(\frac{9}{x+y}+\frac{4}{x-y}=1\)......(ii)

Substituting 1/x+y = u and 1/x−y = v, we get: 

3u + 2v = 2 ……..(iii) 

9u - 4v = 1 …….(iv) 

On multiplying (iii) by 2, we get: 

6u + 4v = 4 …..(v) 

On adding (iv) and (v), we get: 

15u = 5 

⇒u = 5/15 = 1/3 

⇒ 1/x+y = 1/3 

⇒ x + y = 3 …….(vi) 

On substituting u = 1/3 in (iii), we get 

1 + 2v = 2 

⇒2v = 1 

⇒v = 1/2 

⇒ 1/x−y = 1/2 ⇒ x – y = 2 …….(vii) 

On adding (vi) and (vii), we get 

2x = 5

⇒ x = 5/2 

On substituting x = 5/2 in (vi), we have 

5/2 + y = 3

⇒ y = \((3-\frac{5}2)\)= 1/2 

Hence, the required solution is x = 5/2 and y = 1/2 .

29.

Solve for x and y:\(\frac{5}x+\frac{2}y=6\),\(\frac{-5}x+\frac{4}y=-3\)

Answer»

The given equations can be written as

 \(\frac{5}x+\frac{2}y=6\)........(i)
\(\frac{-5}x+\frac{4}y=-3\).......(ii)

Adding (i) and (ii), we get 

6/y = 3 ⇒ y = 2 

Substituting y = 2 in (i), we have 

5/x + 2/2 = 6 ⇒ x = 1 

Hence, x = 1 and y = 2.

30.

Solve for x and y:\(\frac{10}{x+y}+\frac{2}{x-y}=4\),\(\frac{15}{x+y}-\frac{9}{x-y}=-2\),where x ≠ y, x ≠ -y.

Answer»

The given equations are

 \(\frac{10}{x+y}+\frac{2}{x-y}=4\).............(i)

\(\frac{15}{x+y}-\frac{9}{x-y}=-2\).......(ii)

Substituting 1/x+y = u and 1/x−y = v in (i) and (ii), we get: 

10u + 2v = 4 ……..(iii) 

15u - 9v = -2 …….(iv) 

Multiplying (iii) by 9 and (iv) by 2 and adding, we get: 

90u + 30u = 36 – 4

⇒120u = 32 

⇒u = 32/120 = 4/15 

⇒x + y = 15/4 \((∵\frac{1}{x+y}=u)\).........(v)

On substituting u = 4/15 in (iii), we get: 

10 × 4/15 + 2v = 4 

8/3 + 2v = 4 

⇒2v = 4 - 8/3 = 4/3 

⇒v = 2/3 

⇒ x – y = 3/2 \((∵\frac{1}{x-y}=v)\)........(vi)

Adding (v) and (vi), we get 

2x = 15/4 + 3/2 ⇒2x = 21/4 ⇒x = 21/8 

Substituting x = 21/8 in (v), we have 

21/8 + y = 15/4 ⇒y = 15/4 - 21/8 = 9/8 

Hence, x = 21/8 and y = 9/8

31.

Solve for x and y:\(\frac{5}{x+1}+\frac{2}{y-1}\) = \(\frac{1}2,\frac{10}{x+1}-\frac{2}{y-1}\)= \(\frac{5}2\),where x ≠ 1, y ≠ 1.

Answer»

The given equations are

 \(\frac{5}{x+1}+\frac{2}{y-1}\) = \(\frac{1}2\)..........(i)

 \(\frac{10}{x+1}-\frac{2}{y-1}\)\(\frac{5}2\).........(ii)

 Substituting 1/x+1 = u and 1/y−1 = v, we get: 

5u - 2v = 1/2 ……..(iii) 

10u + 2v = 5/2 …….(iv) 

On adding (iii) and (iv), we get: 

15u = 3 

⇒u = 3/15 = 1/5 

⇒ 1/x+1 = 1/5 ⇒ x + 1 = 5 ⇒ x = 4 

On substituting u = 1/5 in (iii), we get 

5 × 1/5 - 2v = 1/2 ⇒ 1 – 2v = 1/2 

⇒2v = 1/2 ⇒v = 1/4 

⇒ 1/y−1 = 1/4 ⇒ y – 1 = 4 ⇒ y = 5 

Hence, the required solution is x = 4 and y = 5.

32.

Solve for x and y:\(\frac{1}{3x+y}+\frac{1}{3x-y}=\frac{3}4\),\(\frac{1}{2(3x+y)}-\frac{1}{2(3x-y)}=-\frac{1}8\)

Answer»

The given equations are

 \(\frac{1}{3x+y}+\frac{1}{3x-y}=\frac{3}4\).........(i)

\(\frac{1}{2(3x+y)}-\frac{1}{2(3x-y)}=-\frac{1}8\)

\(\frac{1}{3x+y}-\frac{1}{3x-y}=-\frac{1}4\) (Multiplying by 2) ……(ii) 

Substituting 1/3x+y = u and 1/3x−y = v in (i) and (ii), we get: 

u + v = 3/4 ……..(iii) 

u – v = − 1/4 …….(iv) 

Adding (iii) and (iv), we get: 

2u = 1/2

⇒ u = 1/4 

⇒3x + y = 4 \((∵\frac1{3x+y}=u)\)........(v)

Now, substituting u = 1/4 in (iii), we get: 

1/4 + v = 3/4 

v = 3/4 - 1/4 

⇒v = 1/2

 ⇒ 3x – y = 2 \((∵\frac1{3x-y}=v)\)....(vi)

Adding (v) and (vi), we get 

6x = 6 ⇒x = 1 

Substituting x = 1 in (v), we have 

3 + y = 4 ⇒y = 1 

Hence, x = 1 and y = 1.

33.

Solve for x and y:3/x+y + 2/x-y = 23/x+y +2/x-y = 2

Answer»

The given equations are 

3/x+y + 2/x-y = 2 ……(i) 

9/x+y - 4/x-y = 1 ……(ii) 

Substituting 1/x+y= u and 1/x-y = v, we get: 

3u + 2v = 2 ……..(iii) 

9u - 4v = 1 …….(iv) 

On multiplying (iii) by 2, we get: 

6u + 4v = 4 …..(v) 

On adding (iv) and (v), we get: 

15u = 5 

⇒u = 5/15 = 1/3 

⇒ 1/x+y = 1/3 

⇒ x + y = 3 …….(vi) 

On substituting u = 1/3 in (iii), we get 

1 + 2v = 2 

⇒2v = 1 

⇒v = 1/2 

⇒ 1/x-y = 1/2 

⇒ x – y = 2 …….(vii) 

On adding (vi) and (vii), we get 

2x = 5

⇒ x = 5/2 

On substituting x = 5/2 in (vi), we have 

5/2 + y = 3 

⇒ y = (3 – 5/2 ) = 1/2 

Hence, the required solution is x = 5/2 and y = 1/2 .

 

34.

Solve for x and y:\(\frac{1}{2(x+2y)}+\frac{5}{3(3x-2y)}=-\frac{3}2\),\(\frac{1}{4(x+2y)}-\frac{3}{5(3x-2y)}=\frac{61}{60}\) where x + 2y ≠ 0 and 3x – 2y ≠ 0

Answer»

The given equations are

 \(\frac{1}{2(x+2y)}+\frac{5}{3(3x-2y)}=-\frac{3}2\)......(i)

\(\frac{1}{4(x+2y)}-\frac{3}{5(3x-2y)}=\frac{61}{60}\).......(ii)

 Putting 1/x+2y = u and 1/3x−2y = v, we get: 

1/2 u + 5/3 v = - 3/2 ……..(iii) 

5/4 u – 3/5 v = 61/60 …….(iv) 

On multiplying (iii) by 6 and (iv) by 20, we get: 

3u + 10v = -9 …..(v) 

25u – 12v = 61/3 …..(vi) 

On multiplying (v) by 6 and (vi) by 5, we get 

18u + 60v = -54 …….(vii) 

125u – 60v = 305/3 ……..(viii) 

On adding(vii) and (viii), we get: 

143u = 305/3 – 54 = 305−162/3 = 143/3 

⇒u = 1/3 = 1/x+2y

⇒x + 2y = 3 …….(ix) 

On substituting u = 1/3 in (v), we get: 

1 + 10v = -9 

⇒10v = -10 

⇒v = -1 

⇒ 1/3x−2y = -1 ⇒3x – 2y = -1 …….(x) 

On adding (ix) and (x), we get: 

4x = 2 

⇒x = 1/2 

On substituting x = 1/2 in (x), we get: 

3/2 – 2y = -1 

2y = (3/2 + 1) = 5/2 

y = 5/4 

Hence, the required solution is x = 1/2 and y = 5/4.

35.

Solve for x and y:5/x+y - 2/x-y = -115/x+y - 7/x-y = 10

Answer»

The given equations are 

5/ x+y - 2/ x-y = -1 ……(i) 

15/ x+y - 7/x-y= 10 ……(ii) 

Substituting 1/x+y = u and 1/x-y = v in (i) and (ii), we get 

5u – 2v = -1 ……..(iii) 

15u + 7v = 10 …….(iv) 

Multiplying (iii) by 3 and subtracting it from (iv), we get 

7v + 6v = 10 + 3 

⇒13v = 13 

⇒v = 1

⇒x – y = 1 (∵ 1/ x-y = ) …..(v) 

Now, substituting v = 1 in (iii), we get 

5u – 2 = -1 

⇒5u = 1 

⇒u = 1/ 5 

x + y = 5 …….(vi) 

Adding (v) and (vi), we get 

2x = 6 

⇒ x = 3 

Substituting x = 3 in (vi), we have 

3 + y = 5 ⇒ y = 5 – 3 = 2 

Hence, x = 3 and y = 2. 

36.

Solve for x and y:\(\frac{2}{3x+2y}+\frac{3}{3x-2y}=\frac{17}{5}\),\(\frac{5}{3x+2y}+\frac{1}{3x-2y}=2\)

Answer»

The given equations are

 \(\frac{2}{3x+2y}+\frac{3}{3x-2y}=\frac{17}{5}\)...........(i)

\(\frac{5}{3x+2y}+\frac{1}{3x-2y}=2\).........(ii)

Substituting 1/3x+2y = u and 1/3x−2y = v, in (i) and (ii), we get: 

2u + 3v = 17/5 ……..(iii) 

5u + v = 2 …….(iv) 

Multiplying (iv) by 3 and subtracting from (iii), we get: 

2u – 15u = 17/5 – 6 

⇒ –13u = −13/5 ⇒u = 1/5

⇒3x + 2y = 5 (∵ 1/3x+2y = ) …..(v) 

Now, substituting u = 1/5 in (iv), we get 

1 + v = 2 ⇒ v = 1 

⇒ 3x – 2y = 1 (∵ 1/3x−2y = ) …….(vi)

Adding(v) and (vi), we get: 

⇒ 6x = 6 ⇒ x = 1 

Substituting x = 1 in (v), we get: 

3 + 2y = 5 ⇒ y = 1 

Hence, x = 1 and y =1.

37.

Define Ration:

Answer»

Ratio : It is a tool to compare two or more quantities (or numbers) having same units by division. 

First term is called antecedent and second term is called consequent.

38.

In A 60 Litres Mixture Of Milk And Water The Ratio Of Milk And Water Is 7:5.How Much Water Should Be Added In The Mixture So That The Ratio Of Milk To Water Becomes 5:7?

Answer»

Mixture 60

Milk 7x=35

Water 5x=25

Milk is not added and kept as it is so 

5x=35   x=7 there by 7x=7*7=49  

Already there is 25 litres of water in the mixture 

so additionally we need to add 24 litres of water.

39.

Write the principal value of cos–1(cos 680°).

Answer»

Given cos-1 (cos 680°)

= cos-1 (cos (720° - 40°)) 

= cos-1 (cos (2 × 360° - 40°)) 

= cos-1 (cos 40°) 

= 40° 

∴ cos-1 (cos 680°) = 40°

40.

Write the value of\(sin^{-1}(sin\frac{3\pi}{5})\).

Answer»

Given sin-1 (sin 3π/5) 

= sin-1 [sin (π – 2π/5)] 

= sin-1 (sin 2π/5) 

= 2π/5 

∴ sin-1 (sin 3π/5) = 2π/5

41.

Write the value of cos(sin-1 x + cos-1 x), |x| ≤ 1.

Answer»

Given |x| ≤ 1

⇒ ± x ≤ 1

⇒ x ≤ 1 or –x ≤ 1

⇒ x ≤ 1 or x ≥ -1

⇒ x ∈ [-1, 1]

Now also given cos (sin-1 x + cos-1 x)

We know that sin-1 x + cos-1 x = π/2

∴ cos (sin-1 x + cos-1 x) = cos (π/2) = 0

42.

Write the value of cos(sin-1 x + cos-1 x), |x| ≤ 1.

Answer»

Given |x| ≤ 1 

⇒ ± x ≤ 1 

⇒ x ≤ 1 or –x ≤ 1 

⇒ x ≤ 1 or x ≥ -1 

⇒ x ∈ [-1, 1] 

Now also given cos (sin-1 x + cos-1 x) 

We know that sin-1 x + cos-1 x = π/2 

∴ cos (sin-1 x + cos-1 x) = cos (π/2) = 0

43.

Write the value of\(sec^{-1}(\frac{1}{2})\).

Answer»

We know that the value of sec-1 (1/2) is undefined as it is outside the range i.e. R – (-1, 1).

44.

Fill in the blanks:The set of values of sec-1 (1/2) is _________.

Answer»

The set of values of sec-1 (1/2) is ɸ.

Domain of sec-1 x is R – (-1,1).

As, -1/2 is outside domain of sec-1 x.

Which means there is no set of value of sec-1 1/2.

So, the solution set of sec-1 1/2 is null set or ɸ.

45.

Write the value of\(cos^{-1}(cos\frac{14\pi}{3})\).

Answer»

Given cos-1 (cos 14π/3) 

= cos-1 [cos (4π + 2π/3)] 

= cos-1 (cos 2π/3) 

= 2π/3 

∴ cos -1 (cos 14π/3) = 2π/3

46.

If cos (sin-1 2/5 + cos-1 x) = 0, then x is equal to(a) 1/5 (b) 2/5 (c) 0 (d) 1

Answer»

(b) 2/5

Given,

cos (sin-1 2/5 + cos-1 x) = 0

So, this can be rewritten as

sin-1 2/5 + cos-1 x = cos-1 0

sin-1 2/5 + cos-1 x = π/2

cos-1 x = π/2 – sin-1 2/5

cos-1 x = cos-1 2/5 [Since, cos-1 x + sin-1 x = π/2]

Hence,

x = 2/5

47.

The domain of the function by f(x) = sin-1 √(x – 1) is(a) [1, 2] (b) [-1, 1] (c) [0, 1] (d) none of these

Answer»

(a) [1, 2]

We know that, sin-1 x is defined for x ∈ [-1, 1]

So, f(x) = sin-1 √(x – 1) is defined if

0 ≤ √(x – 1) ≤ 1

0 ≤ x – 1 ≤ 1

1 ≤ x ≤ 2

Hence,

x ∈ [1, 2]

48.

Why is there uneven rainfall in India?

Answer»

Because the winds that bring rainfall blow from various directions.

49.

Define: Climatic condition.

Answer»

Climate is an average weather condition that exists in an area over a long period of time. Conditions related to climate or weather are called climatic conditions.

50.

Forests are invaluable treasure of India. Give reason.

Answer»
  • India possesses a very large area of forests.
  • India has evergreen, deciduous, thorny and tidal forests.
  • India ranks 10th in terms of variety in vegetation.
  • These forests provide livelihood to numerous people.
  • We get several medicinal herbs, paper, timber, sealing wax, rubber, etc. from forests.
  • Thus, forests are invaluable treasure of our country.