Question

guys help me out to prove this: For two sets A and B, show that the following statements are equivalent :
a. A is a subset of B
b.A union B = A
c. A intersection B =A
ur help will b appreciated :)

Answer 1

Since A is a subset of B, if x is in A, then x is in B. Therefore, if x is not in B, then x is not in A. But "not in B" means "in complement of B," and similarly for A. Thus if x is in B', then x is in A', the definition of "B' is a subset of A'." That completes the proof.

Answer 2

A U B

"A union B"

everything
that is in
either of the sets

Answer 3

{1, 2, 3} is a union b

Answer 4

A ^ B
or


"A intersect B"

only the things
that are in
both of the sets

answer



{2}

Answer 5

A ^ B
or


"A intersect B"

only the things
that are in
both of the sets

answer



{2}

Answer 6

thank you very much,..
i shud be one of ur fans :D

Answer 7

thanx