Question

identify the following as null set and singleton set
1. A = {x | x € N, 1 < x < 2}
2. B = {point of intersection of two lines}
3. C = {x : x is an even prime number greater than 2}
4. Q={x | x is an even prime number}
5. H = { x : x2=9, x is even}​

Answer 1

1) Null set ( as there is no natural number between 1 and 2 )

2) Singleton set ( as 2 lines interesect in 1 point only ; provided they are not Parallel or coincident )

3) Null set ( as there is no even prime number except 2 )

4) Singleton set ( as there is only one even prime number i.e. 2 )

5) Null set ( as x² = 9 => x = 3 which is odd )