Which of the following sets are equal?
A= {x:x ∈ N, x < 3},
B= {1, 2}, C= {3, 1}
D = {x : x ∈ N, x is odd, x < 5},
E= (1, 2, 1, 1}, F= {1, 1, 3}.
A = x is a natural number. And x is less than 3
So all natural numbers less than 3 constitute set A.
{1, 2}
A ={1, 2}
B = {1, 2}
C = {1, 3}
D = x is a natural number. And x is less than 5 and is odd.
So all odd natural numbers less than 5 constitute set D.
{1, 3}
D = {1, 3}
E ={1, 2, 1, 1}
We don’t repeat same elements in a set.
∴ E = {1, 2}
F ={1, 1, 3}
We don’t repeat same elements in a set.
∴ F = {1, 3}
∴ A = {1, 2}
B = {1, 2}
C = {1, 3}
D = {1, 3}
E = {1, 2}
F = {1, 3}
Now, we can see clearly that set A, B, E are equal and set C, D, F are equal.