Question

Find, which of the following sets are empty : 

(i) The set of points of intersection of two parallel lines. 

(ii) A = {x : x ∈ N and 5 < x < 6} 

(iii) B = {x : x2 + 4 = 0, x ∈ N} 

(iv) C = {even numbers between 6 & 10} 

(v) D = {prime numbers between 7 & 11} 

Note : The set, which has no element in it, is called the empty or null set.

Answer 1

(i) "The set of points of intersection of two parallel lines'' is an empty set be-cause two parllel lines do not intersect anywhere.