Mathematics
State whether the given set is finite or infinite :
(i) Set of all even natural numbers.
(ii) Set of all odd integers.
(iii) Set of all rivers in India.
(iv) Set of all points on a line segment 1 cm long.
(v) Set of all factors of 1200.
(vi) Set of all multiples of 6.
(vii) Set of all drops of water in a bucket.
Answer
(i) Set of all even natural numbers.
Natural numbers go on forever (2, 4, 6, 8, …..), so the counting process never ends.
∴ It is an infinite set.
(ii) Set of all odd integers.
Integers extend infinitely in both positive and negative directions (…., -3, -1, 1, 3, ….).
∴ It is an infinite set.
(iii) Set of all rivers in India.
Although there are many rivers, the total number is a specific, countable figure that can be listed.
∴ It is a finite set.
(iv) Set of all points on a line segment 1 cm long.
Mathematically, a line segment consists of an uncountable infinity of points, regardless of its length.
∴ It is an infinite set.
(v) Set of all factors of 1200.
Every number has a limited (finite) number of factors.
∴ It is a finite set.
(vi) Set of all multiples of 6.
Multiples are generated by multiplying 6 by natural numbers (6, 12, 18, ….), which are endless.
∴ It is an infinite set.
(vii) Set of all drops of water in a bucket.
The number is extremely large and difficult to count.
∴ It is an infinite set.
Related Questions
Identify the null sets among the following :
(i) A = {x : x is a whole number, x < 1}.
(ii) B = {x : x is a number, x > x}.
(iii) C = {x : x is an even prime number}.
(iv) D = {x : x ∈ I, x2 = -4}.
(v) E = {x : x is a perfect square number, 40 < x < 50}.
(vi) F = {x : x ∈ N, 5 < x < 6}.
Identify whether the given pair consists of equal or equivalent but not equal sets or none :
(i) A = set of letters of the word 'FLOWER'.
B = set of letters of the word 'FOLLOWER'.(ii) C = {x : x ∈ N, x + 5 = 6} and D = {x : x ∈ W, x < 1}.
(iii) E = set of first five whole numbers.
F = set of first five natural numbers.(iv) G = {a, b, c} and H = {x, y, z}.
(v) J = {x : x ∈ N, x ≠ x} and K = {x : x ∈ N, 6 < x < 7}.