Question

Which of the following are examples of the null set
(i) Set of odd natural numbers divisible by 2
(ii)
Set of even prime numbers
(iii) {
x : x
is a natural numbers,
x
< 5 and
x
> 7 }
(iv) {
y : y
is a point common to any two parallel lines}

Answer 1

@ruizgeorge

Answer 2

i. odd numbers can't be divisible by 2 (This is a null set!)
ii. 2 is an even prime number (This is NOT a null set)
iii. {x : x is a natural numbers, x< 5 and x > 7 } you can't find a number less than 5 and greater than 7 at same time (This is a null set)
iv. {y : y is a point common to any two parallel lines} Parallel lines don't have common points (This is a null set)

Answer 3

Thank you sir