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Let A and B be sets. Prove that (A n B) u (A\B) = A.

a little confused on how to answer the question above.

thanks
Reply 1
Avatar for Haddar
Haddar
6
Original post by DORI
a little confused on how to answer the question above.

thanks


Lets say A=1 2 3 4
and B=1 5 6 7

So AnB is 1
A/B is 1 2 3 4
AnB u A/B is 1 2 3 4 which is A

At least i think its right :biggrin:
Try expanding out and see where you can go from there. (A∩B)∪C=(A∪C)∩(B∪C)(A \cap B) \cup C = (A \cup C) \cap(B \cup C)

Original post by Haddar
Lets say A=1 2 3 4
and B=1 5 6 7

So AnB is 1
A/B is 1 2 3 4
AnB u A/B is 1 2 3 4 which is A

At least i think its right :biggrin:

Examples never work in proving something man lol, unless you show it works for every single plausible example. In which case you'd be here all day.
Reply 3
Avatar for Haddar
Haddar
6
Original post by Dilzo999
Try expanding out and see where you can go from there. (A∩B)∪C=(A∪C)∩(B∪C)(A \cap B) \cup C = (A \cup C) \cap(B \cup C)


Examples never work in proving something man lol, unless you show it works for every single plausible example. In which case you'd be here all day.


I was providing an example on how one would answer the question he can take it from there and try to prove it.
Original post by Haddar
I was providing an example on how one would answer the question he can take it from there and try to prove it.

No you weren't. You just gave random values and showed the equation is satisfied. Have you even done set theory or are just talking out of your ass?

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