# venn diagram

• Jul 22nd 2013, 07:22 PM
icelated
venn diagram
I am trying to draw a venn diagran by hand for each of these combinations of sets A,B, and C

$(A - B) \cup (A - C) \cup (B - C)$

This has me rather stumped.
What i did was shade in all of A, B, C
Then started taking away B from A, C from A, and finally C from B

Which left me with what you see in the attached pic. Is this correct?
If not can you help!

Attachment 28877

Thank you
• Jul 22nd 2013, 07:58 PM
Plato
Re: venn diagram
Quote:

Originally Posted by icelated
I am trying to draw a venn diagran by hand for each of these combinations of sets A,B, and C

$(A - B) \cup (A - C) \cup (B - C)$

This has me rather stumped.
What i did was shade in all of A, B, C
Then started taking away B from A, C from A, and finally C from B
Which left me with what you see in the attached pic. Is this correct?
If not can you help!

Attachment 28877

If the question is as you posted it then no your diagram is not correct.

You have the union of three sets. In unions we never "loose" members.

Diagram each of $(A-B),~(A-C),~\&~(B-C)$. That is three in all.
Then merge the three diagrams into one.
• Jul 22nd 2013, 08:45 PM
icelated
Re: venn diagram
Okay, so i am having hard time doing what you said. However, this is what i came up with. Is this correct?

If i take them in 3 drawings then i shade in A then take away B? Then, do the same for the other 2 drawings then add them together?
This is what i did.Attachment 28880
• Jul 22nd 2013, 09:01 PM
johng
Re: venn diagram
Hi,
No, still not right. A venn diagram partitions the union of the 3 sets into 7 pieces. So one strategy is draw the first set A-B, then the 2nd A-B and then the 3rd B-C. Draw the union of the 3 sets by merging the solid pieces (of the 7).
See the attachment:
Attachment 28883
• Jul 22nd 2013, 09:41 PM
icelated
Re: venn diagram
I had it right when i did the 3 pieces but wrong when i put them together. Thank you!!!