# Venn Diagrams confusion.

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. But surely A-B should look like this? I'm really unsure about the steps I have to take to get to each step.

Could someone explain please?

Thanks!

• Why should $A-B$ not have elements from $A$ that are not in $B$? – user21436 May 1 '12 at 9:57
• Oops i think im getting confused between A-b and ~A and ~B – Xabi May 1 '12 at 9:59
• Fine, so, do you get that the second diagram is not right? – user21436 May 1 '12 at 10:01
• Yes, does that mean the first one is right? – Xabi May 1 '12 at 10:01
• 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. – user21436 May 1 '12 at 10:07

## 1 Answer

It should be like this : • yes exacly @pedja ,as i indicated in my comment +1 – dato datuashvili May 1 '12 at 10:15