Question

Given the following sets.

A = {0, 1, 2, 3}

B = {a, b, c, d}

C = {0, a, 2, b}

Find A B

{0, 1, 2, 3}
{a, b, c, d}
{0, a, 2, b}
empty set
{0, a}

Answer 1

is it
1) \(A\cap B\) or
2) \(A\cup B\) ?

Answer 2

yeahh the first one

Answer 3

do you know the meaning of \(\cap\) ?

Answer 4

\(A\cap B\) is a set called "intersection of A and B".
the elements of \(A\cap B\) are the elements that are in A AND in B.
If there are none, then this set is empty.

Answer 5

any idea?

Answer 6

noo hah im confused

Answer 7

take A={0,1,2,3}, B={a,b,c,d}.
What are the elements that are in both sets?

Answer 8

in the brackets ?

Answer 9

yes,
so what you do is
-look at 0, then check if it's in B -> it's not in B
-look at 1, then check if it's in B -> it's not in B
-look at 2, then check if it's in B -> it's not in B
-look at 3, then check if it's in B -> it's not in B

Therefore no elements of A are in B. They have nothing in common. Then \(A\cap B=\varnothing\) (empty set).

Answer 10

Draw a picture to help her understand. Hint: Venn Diagrams