CBSE NCERT Solutions For Class 11th Maths Chapter 1 : Set. NCERT Solutins For Class 11 Mathematics. Exercise 1.1, Exercise 1.2, Exercise 1.3, Exercise 1.4, Exercise 1.5, Exercise 1.6, (Miscellaneous Excercise) many more solutions

**Exercise 1.5**

**Question 1:**

Let U ={1, 2, 3; 4, 5, 6, 7, 8, 9}, A = {1, 2, 3, 4}, B = {2, 4, 6, 8} and C = {3, 4, 5, 6}. Find

Answer

U ={1, 2, 3, 4, 5, 6, 7, 8, 9}

A = {1, 2, 3, 4}

B = {2, 4, 6, 8}

C = {3, 4, 5, 6}

**(i) **

**(ii) **

**(iii) **

**(iv) **

**(v) **

**(vi) **

**Question 2:**

If U = {*a, b, c, d, e, f, g, h*}, find the complements of the following sets:

- A = {
*a, b, c*} - B = {
*d, e, f, g*}

- C = {
*a, c, e, g*} - D = {
*f*,*g*,*h*,*a*} Answer

U = {*a, b, c, d, e, f, g, h*}

- A = {
*a, b, c*} - B = {
*d, e, f, g*} - C = {
*a, c, e, g*} - D = {
*f*,*g*,*h*,*a*}

**Question 3:**

Taking the set of natural numbers as the universal set, write down the complements of the following sets:

- {
*x*:*x*is an even natural number} - {
*x*:*x*is an odd natural number} - {
*x*:*x*is a positive multiple of 3} - {
*x*:*x*is a prime number} - {
*x*:*x*is a natural number divisible by 3 and 5} - {
*x*:*x*is a perfect square} - {
*x*:*x*is perfect cube} - {
*x*:*x*+ 5 = 8} - {
*x*: 2*x*+ 5 = 9} - {
*x*:*x*≥ 7} - {
*x*:*x*∈ N and 2*x*+ 1 > 10}

Answer

U = N: Set of natural numbers

**(i) **{*x*:** ***x*** **is an even natural number}´ = {*x*:** ***x*** **is an odd natural number}

- {
*x*:*x*is an odd natural number}´ = {*x*:*x*is an even natural number} - {
*x*:*x*is a positive multiple of 3}´ = {*x*:*x*∈ N and*x*is not a multiple of 3} - {
*x*:*x*is a prime number}´ ={*x*:*x*is a positive composite number and*x*= 1} - {
*x*:*x*is a natural number divisible by 3 and 5}´ = {*x*:*x*is a natural number that is not divisible by 3 or 5} - {
*x*:*x*is a perfect square}´ = {*x*:*x*∈ N and*x*is not a perfect square} - {
*x*:*x*is a perfect cube}´ = {*x*:*x*∈ N and*x*is not a perfect cube} - {
*x*:*x*+ 5 = 8}´ = {*x*:*x*∈ N and*x*≠ 3} - {
*x*: 2*x*+ 5 = 9}´ = {*x*:*x*∈ N and*x*≠ 2} - {
*x*:*x*≥ 7}´ = {*x*:*x*∈ N and*x*< 7} - {
*x*:*x*∈ N and 2*x*+ 1 > 10}´ = {*x*:*x*∈ N and*x*≤ 9/2}

**Question 4:**

If U = {1, 2, 3, 4, 5,6,7,8, 9}, A = {2, 4, 6, 8} and B = {2, 3, 5, 7}. Verify that

**(i) (ii) **

Answer

U = {1, 2, 3, 4, 5, 6, 7, 8, 9}

A = {2, 4, 6, 8}, B = {2, 3, 5, 7}

**(i)**

**(ii)**

**Question 5:**

Draw appropriate Venn diagram for each of the following:

Answer

**(i) **

**(ii) **

**(iii) **

**(iv) **

**Question 6:**

Let U be the set of all triangles in a plane. If A is the set of all triangles with at least one angle different from 60°, what is ?

Answer

is the set of all equilateral triangles.

**Question 7:**

Fill in the blanks to make each of the following a true statement:

**(i) (ii) **Φ′** **∩** **A = …

**(iii) **

**(iv) **

Answer

**(i) **

**(ii) **Φ′** **∩** **A = U** **∩** **A = A

∴ Φ′ ∩ A = A

- A ∩ A′ = Φ
- U′ ∩ A = Φ ∩ A = Φ

∴ U′ ∩ A = Φ

### NCERT Solutions for Class XI Maths: Chapter 1 – Set

**Exercise 1.1 Solutions****Exercise 1.2 Solutions****Exercise 1.3 Solutions****Exercise 1.4 Solutions****Exercise 1.5 Solutions****Exercise 1.6 Solutions****Miscellaneous Solutions**