Question

Let ? = { ? / ? |? ∈ ? ??? ? ∈ ? ??? ? ≥ 2 ??? ? < 4 ??? ? > 0 ??? ? < 4}

a. What is A?

b. What is |A|?

Answer 1

a.

A= a/b : a geq 2 less than 4 b> 0 b<4

Given A = { a/b : and b> 0 , b< 4 }

since a is an integer with so possible values of a are { 2 , 3}

Also b >0 , b< 4 so possible values of b are { 1 , 2 , 3 }

So A = { a/b : and b> 0 , b< 4 }

A = { 2/1 , 2/2 , 2/3 , 3/1 , 3/2 , 3/3 }

A = { 2 , 1 , 2/3 , 3 , 3/2 , 1 }

A = { 1 , 2 , 3 , 2/3 , 3/2 }

Hence ,

Answer : A = { 1 , 2 , 3 , 2/3 , 3/2 }

| A | = 5 .

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If you have any doubt or need more clarification at any step please comment.

b. As the set A contains five element hence ,