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



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