You're on a roll — here are the solutions to the math problems.
Question (e) from the first image:
Which is the set of prime numbers less than 10?
The prime numbers less than 10 are 2, 3, 5, and 7. (1 is not a prime number).
The correct option is ii. {2,3,5,7}.
4. A is the set of natural numbers between 0 and 10 exclusive.
- a) List the elements of the set A.
Natural numbers start from 1. "Between 0 and 10 exclusive" means numbers greater than 0 and less than 10.
A={1,2,3,4,5,6,7,8,9}
- b) Use ∈ or ∈/ if 2, 3, 0, 9, 11 belong or do not belong to the set A.
- 2∈A
- 3∈A
- 0∈/A
- 9∈A
- 11∈/A
- c) Write the set in set-builder notation.
A={x∣x∈N,0<x<10}
5. a) List the members of the following sets.
- A = {odd numbers from 0 to 10}
A={1,3,5,7,9}
- B = {prime numbers between 10 and 24}
B={11,13,17,19,23}
- C = {multiples of 7 between 6 and 50}
C={7,14,21,28,35,42,49}
b) Which sets are equivalent among A, B and C?
Equivalent sets have the same number of elements.
- Number of elements in A, ∣A∣=5.
- Number of elements in B, ∣B∣=5.
- Number of elements in C, ∣C∣=7.
Sets A and B have the same number of elements.
The equivalent sets are AandB.
6. Given that P={0,1,3,5}, Q={5,3,1}, R={0}, S={1}, T=ϕ and S={3,1,5}.
Assumption: The second definition of S, S={3,1,5}, overwrites the first definition S={1}.
So, the sets are: P={0,1,3,5}, Q={5,3,1}, R={0}, S={3,1,5}, T=ϕ.
- a) Write down the number of elements in each set.
- ∣P∣=4
- ∣Q∣=3
- ∣R∣=1
- ∣S∣=3
- ∣T∣=0
- b) Which of the sets are equal?
Equal sets contain exactly the same elements.
Q={5,3,1} and S={3,1,5} contain the same elements.
The equal sets are QandS.
- c) Which of the sets have equal number of elements but the sets are not equal?
From part (a), ∣Q∣=3 and ∣S∣=3. However, Q and S are equal sets. There are no other pairs of sets with an equal number of elements that are not themselves equal.
None
7.
- a) If A={a,b,c,d} and B={a,b,c,d,e}, all elements of A are also the elements of B, but again A=B. Why?
A=B because set B contains an element 'e' that is not present in set A. For two sets to be equal, they must contain exactly the same elements.
- b) If P={g,o,d} and Q={c,u,p}, why are P and Q not equal sets? But P is equivalent to Q. Why?
P and Q are not equal sets because they do not contain the same elements (e.g., 'g' is in P but not in Q). They are equivalent sets because they have the same number of elements: ∣P∣=3 and ∣Q∣=3.
8. A={1,2,3,4,5} is a given set.
Write the following subsets of A (i) by listing (ii) by set-builder notation.
- a) B = Set of elements of A that are prime numbers
- (i) B={2,3,5}
- (ii) B={x∣x∈A and x is a prime number}
- b) C = Set of elements of A that are even numbers
- (i) C={2,4}
- (ii) C={x∣x∈A and x is an even number}
- c) D = Set of elements of A that are odd numbers
- (i) D={1,3,5}
- (ii) D={x∣x∈A and x is an odd number}
- d) E = Set of elements of A that are even prime numbers
- (i) E={2}
- (ii) E={x∣x∈A and x is an even prime number}
- e) F = Set of elements of A that are between 1 and 4
- (i) F={2,3}
- (ii) $F = {x \mid x \in A \text{ and 1 <