- #1
supasupa
- 24
- 0
The question is
If A U B is a subset of A intersect B, then prove that A=B
Now i can see this in my head and it makes sense that the elements in set A and Set B would have to be the same. The problem that i have with subset questions is how to prove that this is the case. I can start by saying
For all x ( x is an element of (A U B) --> x is an element of (A intersect B))
( x is an element of (A U B) --> x is an element of A AND B))
( x is an element of (A U B) --> x is an element of A AND x is an element of B))
Where do i go from here? Any help would be great
If A U B is a subset of A intersect B, then prove that A=B
Now i can see this in my head and it makes sense that the elements in set A and Set B would have to be the same. The problem that i have with subset questions is how to prove that this is the case. I can start by saying
For all x ( x is an element of (A U B) --> x is an element of (A intersect B))
( x is an element of (A U B) --> x is an element of A AND B))
( x is an element of (A U B) --> x is an element of A AND x is an element of B))
Where do i go from here? Any help would be great