CBSE.mocha

Grade 11 - Mathematics

CHAPTER 1 : Sets

Exercise 1.1

  1. Which of the following are sets ? Justify your answer.
    1. The collection of all the months of a year beginning with the letter J.
    2. answer
    3. The collection of ten most talented writers of India.
    4. answer
    5. A team of eleven best-cricket batsmen of the world.
    6. answer
    7. The collection of all boys in your class.
    8. answer
    9. The collection of all natural numbers less than 100.
    10. answer
    11. A collection of novels written by the writer Munshi Prem Chand.
    12. answer
    13. The collection of all even integers.
    14. answer
    15. The collection of questions in this Chapter.
    16. answer
    17. A collection of most dangerous animals of the world.
    18. answer
  2. Let A = {1, 2, 3, 4, 5, 6}. Insert the appropriate symbol ∈ or ∉ in the blank spaces:
    1. 5 …… A
    2. 8 …… A
    3. 0 …… A
    4. 4 …… A
    5. 2 …… A
    6. 10 …… A
    answer
  3. Write the following sets in roster form:
    1. A = {x: x is an integer and –3 ≤ x < 7}
    2. B = {x: x is a natural number less than 6}
    3. C = {x: x is a two-digit natural number such that the sum of its digits is 8}
    4. D = {x: x is a prime number which is divisor of 60}
    5. E = The set of all letters in the word TRIGONOMETRY
    6. F = The set of all letters in the word BETTER
    answer
  4. Write the following sets in the set-builder form:
    1. {3, 6, 9, 12}
    2. {2, 4, 8, 16, 32}
    3. {5, 25, 125, 625}
    4. {2, 4, 6, …}
    5. {1,4,9, … 100}
    answer
  5. List all the elements of the following sets:
    1. A = {x : x is an odd natural number}
    2. B = {x : x is an integer, −1⁄2 < x < 9⁄2;}
    3. C = {x : x is an integer, x2 ≤ 4}
    4. D = {x : x is a letter in the word “LOYAL”}
    5. E = {x : x is a month of a year not having 31 days}
    6. F = {x : x is a consonant in the English alphabet which precedes k}
    answers
  6. Match each of the set on the left in the roster form with the same set on the right described in set-builder form:
    1. {1, 2, 3, 6} (a) {x : x is a prime number and a divisor of 6}
    2. {2, 3} (b) {x : x is an odd natural number less than 10}
    3. {M, A, T, H, E, I, C, S} (c) {x : x is a natural number and divisor of 6}
    4. {1, 3, 5, 7, 9} (d) {x : x is a letter of the word MATHEMATICS}
    answer