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I was doing the following question.

    illustrate the following using a venn diagram      A – B =  ~(~A ∪ B)     where as usual A-B={x : x ∈ A & x ∉ B} 

I got the following.

i got the following

But surely A-B should look like this?

enter image description here

I'm really unsure about the steps I have to take to get to each step.

Could someone explain please?

Thanks!

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    Why should $A-B$ not have elements from $A$ that are not in $B$?2012-05-01
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    Oops i think im getting confused between A-b and ~A and ~B2012-05-01
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    Fine, so, do you get that the second diagram is not right?2012-05-01
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    Yes, does that mean the first one is right?2012-05-01
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    Yes, sure it does. What you have first is right one for $A-B$ and the second diagram is the right one for $\lnot A \cap \lnot B$ which is also $(A \cup B)^c$ y DeMorgan's laws.2012-05-01
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    generally before A-B,you should show A intersection B and adter that,A-B would be all A except points which would be in intersection region2012-05-01

1 Answers 1

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It should be like this :

enter image description here

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    yes exacly @pedja ,as i indicated in my comment +12012-05-01