If A = {x : x ϵ R, x < 5} and B = {x : x ϵ R, x > 4}, find A ∩ B.
A = {x: x ∈ R, x < 5}
As x takes all real values upto 5 hence the set A will contain all numbers from -∞ to 5
A = (-∞, 5)
B = {x: x ∈ R, x > 4}
As x takes all real values greater than 4 hence the set B will contain values from 4 to ∞
B = (4, -∞)
Hence their intersection or the common part between sets A and B would be values from 4 to 5
Hence A ∩ B = (4, 5)
Representing the sets on number line