Question

What is n(A) and n(B) in sets lesson? ​

Answer 1

Set membership x ∈ X means x is an element of the set X. ... The set of natural numbers N has elements 0,1,2,3,.... Intersection X ∩ Y is defined by: x ∈ X ∩ Y if and only if x ∈ X and x ∈ Y .