Question

If A= {x:x=3n, n€Z} and B= {x:x=4n,n€Z} then find A intersection B

Answer 1

Set Intersection

Given:

• A = {x: x = 3n, n in Z}
• B = {x: x = 4n, n in Z}

To find: A ∩ B

Solution:

• A = {x: x = 3n, n in Z}
• = {3, 6, 9, 12, 15, 18, 21, 24, ...}

• B = {x: x = 4n, n in Z}
• = {4, 8, 12, 16, 20, 24, ...}

• Now, A ∩ B
• = {x: x is in both A and B}
• = {12, 24, ...}

• This shows the elements of the set A ∩ B are of the form 12n, where n in Z.

• A general form of A ∩ B is
• = {x: x = 12n, n in Z}.

Answer: A ∩ B = {x: x = 12n, n in Z}