Question
Question: Write the following sets in the set builder form : (i) O = {0} (ii) P = {2} (iii) Q = {1, 4, 9, 16} ...
Write the following sets in the set builder form : (i) O = {0} (ii) P = {2} (iii) Q = {1, 4, 9, 16} (iv) R = {2, 3, 5, 7} (v) S = {1, 3, 9, 27} (vi) T = {A, E, I, O, U} (vii) V = {0, 3, 6, 9, ...}

(i) O={x∣x=0}
(ii) P={x∣x=2}
(iii) Q={x∣x=n2,n∈N and 1≤n≤4}
(iv) R={x∣x is a prime number and x<10}
(v) S={x∣x=3n,n∈W and 0≤n≤3}
(vi) T={x∣x is a vowel in the English alphabet}
(vii) V={x∣x=3n,n∈W}
Solution
To write a set in set-builder form, we describe the common property shared by all the elements of the set.
(i) O = {0}
This set contains only the element 0.
In set-builder form:
O={x∣x=0}
(ii) P = {2}
This set contains only the element 2.
In set-builder form:
P={x∣x=2}
(iii) Q = {1, 4, 9, 16}
Observe the pattern:
1=12
4=22
9=32
16=42
The elements are squares of natural numbers from 1 to 4.
In set-builder form:
Q={x∣x=n2,n∈N and 1≤n≤4}
(iv) R = {2, 3, 5, 7}
Observe the pattern:
These are the first four prime numbers.
In set-builder form:
R={x∣x is a prime number and x<10} (or x≤7)
(v) S = {1, 3, 9, 27}
Observe the pattern:
1=30
3=31
9=32
27=33
The elements are powers of 3, where the exponent ranges from 0 to 3.
In set-builder form:
S={x∣x=3n,n∈W and 0≤n≤3} (where W denotes whole numbers)
Alternatively, using integers: S={x∣x=3n,n∈Z and 0≤n≤3}
(vi) T = {A, E, I, O, U}
Observe the pattern:
These are the vowels in the English alphabet.
In set-builder form:
T={x∣x is a vowel in the English alphabet}
(vii) V = {0, 3, 6, 9, ...}
Observe the pattern:
0=3×0
3=3×1
6=3×2
9=3×3
...
The elements are non-negative multiples of 3.
In set-builder form:
V={x∣x=3n,n∈W} (where W denotes whole numbers)
Alternatively, using integers: V={x∣x=3n,n∈Z and n≥0}