Class 11 Maths Chapter 1 Sets Lecture 4

Lecture - 4 Chapter 1 Sets

Don’t let the fear of losing be greater than the excitement of winning. – Robert Kiyosaki

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NCERT EXERCISE 1.5
  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
  • (i) A′
  • (ii) B′
  • (A ∪ C)′
  • (A ∪ B)′
  • (v) (A′)′
  • (B – C)′
  1. If U = { a, b, c, d, e, f, g, h}, find the complements of the following sets:
  • (i) A = {a, b, c}
  • (ii) B = {d, e, f, g}
  • C = {a, c, e, g}
  • D = { f, g, h, a}
  1. 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 a perfect cube}
  • { x : x + 5 = 8 }
  • { x : 2x + 5 = 9}
  • { x : x ≥ 7 }
  • { x : x ∈ N and 2x + 1 > 10 }
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  1. 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) (A ∪ B)′ = A′ ∩ B′
  • (ii) (A ∩ B)′ = A′ ∪ B′
  1. Draw appropriate Venn diagram for each of the following:
  • (i) (A ∪ B)′,
  • (ii) A′ ∩ B′,
  • (A ∩ B)′,
  • A′ ∪ B′
  1. 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 A′?
  1. Fill in the blanks to make each of the following a true statement:
  • (i) A ∪ A′ = . . . 
  • (ii) f′ ∩ A = . . .
  • A ∩ A′ = . . .
  • U′ ∩ A = . . .
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