Pedagogy of Mathematics (Part II) - Set language introduction and Ex.1.7, Set Language, Maths, IX std Maths, Samacheerkalvi maths, II year B.Ed., Pedagogy,

1. PEDAGOGY OF
MATHEMATICS – PART II
By
Dr. I. Uma Maheswari
Principal
Peniel Rural College of Education,Vemparali, Dindigul District
iuma_maheswari@yahoo.co.in

2. STD IX
CHAPTER 1 – SET LANGUAGE
Ex - 1.7

3. √
√
√
√
√
Hint: P =
{0}
Hint: (A’) = A= {2, 3, 4,
5}
Hint: B ⊆ A ⇒ A ∩ B =
B
Hint: Number of
non-empty subsets
= 2 – 1 = 8 – 1 = 7

4. √
√
√
√
√
Hint: Empty set is an improper
subset
Hint: B – A = B ⇒ A and B are disjoint
sets.
Hint: A ∆ B = { 60, 85, 75, 90, 70} ⇒ n(A ∆ B) = 5 ⇒ n(P(A ∆ B)) =
25 = 32

5. √
√
√
√
Hint: P(A) = {Φ
{Φ}}
Hint: n(A ∪ B) = n(A) + n(B) – n(A n B) ⇒ 50 = 35 + 20 – n(A ∩ B) ⇒ n(A
∩ B) = 5
Hint:
U = {1, 2, 3, 4, 5, 6, 7, 8,
9}
A = {1, 2, 3, 5, 8}
B = {2, 5, 6, 7, 9}
A ∪ B = {1,2, 3, 5, 6, 7,
8,9}
(A ∪ B)’ = {4},
n(A ∪ B)’ = 1
Hint: P – (Q ∩ R) = (P – Q) ∪ (P
– R)

6. Answer:
(4) (A ∩ B)’ = A’ ∪ B’
Hint: (1) (A – B) = A ∩ B ✘
(2) A – B = B – A ✘
(3) (A ∪ B) = A’ ∪ B’ ✘
(4) (A ∩ B)’ = A’ ∪ B’ ✓

7. Answer:
(A) 10
Hint:
n(A ∪ B ∪ C) = n(A) + n(B) + n(C) – n(A ∩
B) – n(B ∩ C) – n(C ∩ A) + n(A ∩ B ∩ C)
100 = 4x + 6x + 5x – 20 – 15 – 25 + 10
100 = 15x -60 + 10
100 = 15x – 50
∴ 15x = 100 + 50 = 150
x = 10

8. Answer:
(4) Φ
Hint: (A – B) ∩ (B – C) is equal to Φ
Answer:
(3) Set of isoceles right triangles
Hint:

9. Answer:
(3) Z – (X ∩ Y)
Hint: Z – (X ∩ Y)
Answer:
(1) 5
Hint: 40 + 35 + 20
+ x = 100%
95% + x = 100%
x = 5%