## Discrete Math Simplifying

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### Discrete Math Simplifying

I am in desperate need of help simplifying these. I have been working on these two questions for 3 days now.

(B – A) U ( B ∩ A)

_____
(A - B) U A
compstudent
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### Re: Discrete Math Simplifying

First problem: B B-A is all of B outside of A, while A∩B is all of B inside A, so the union is B.

Second problem all space: A-B ≤ A, Therefore complement reverses the inequality. So the union contains A and its complement - all space.
mathman
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Joined: Sun May 27, 2007 7:02 pm

### Re: Discrete Math Simplifying

First off, thank you so much for replying Mathman.

However, I am still confused Is it like distributing? I have been looking at my student manual and can only understand when I am given steps. But the questions I am having problems with does not have any sample steps. All of the ones in my student manual are all about U and not - Can you break it down to me barney style? I hope I pass this course. This is my first week in the class.
compstudent
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Posts: 3
Joined: Thu Mar 17, 2011 3:18 pm

### Re: Discrete Math Simplifying

mathman wrote:Second problem all space: A-B ≤ A, Therefore complement reverses the inequality. So the union contains A and its complement - all space.

So does that mean? the final result will be B∩A when I simplify it?
compstudent
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Posts: 3
Joined: Thu Mar 17, 2011 3:18 pm

### Re: Discrete Math Simplifying

compstudent wrote:
mathman wrote:Second problem all space: A-B ≤ A, Therefore complement reverses the inequality. So the union contains A and its complement - all space.

So does that mean? the final result will be B∩A when I simplify it?

No. The final result is the union of A and A' (complement), which is the entire set. You don't have a symbol for it.
mathman
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