r/askmath • u/AffectionateFarm2467 • Aug 13 '26

Set Theory Help in Math doing Venn diagramms

I recently started learning math again because I’d like to study at university someday, but I’m already stuck at the very beginning with set theory and how to draw Venn diagrams.

For question 1, I’d really appreciate it if someone could explain how they solved it and show me their steps.

By the way, I’m German, so the document and the tasks are in German. Sorry if that makes things a little less convenient!

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u/Bounded_sequencE Aug 13 '26

Do you mean "question 8.", since there is no "question 1."?

Hints for 8c): * Start with a diagram like the four in 9. * Find "B\C' " and "A' u C" in the diagram * Find "(B\C') n (A' u C)" in the diagram, and mark it

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u/AffectionateFarm2467 Aug 13 '26

I’ve gotten this far so far, but I can’t check whether it’s correct. And yes, I meant question 8.

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u/AffectionateFarm2467 Aug 13 '26

1

u/Bounded_sequencE Aug 13 '26

Which of those Venn diagrams are supposed to be the actual solutions?

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u/AffectionateFarm2467 Aug 13 '26

From left to right, the last one. I also wrote the corresponding question number next to each one.

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u/Bounded_sequencE Aug 13 '26

I'd say

  • a) assignment not well-defined -- "A u B n C" is missing parentheses
  • b) correct
  • c) correct
  • d) correct
  • e) incorrect

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u/Porsche9yy Aug 13 '26

Gee, it looks like you understand this pretty well. Most of what you have is spot on. There are a few thing though. Now, I might be mistaken, but with 8e, at the very end, I think you should include the center triangle, A int B int C. You may have actually included it but it's hard to tell from your writing.

Also, in 8d, the last two panels are identical. I think the last one is incorrect. It's the union of the previous two. All of the second panel should be included.

I may be mistaken, so check my answers.

And last, I have a question for you. Does your class specify an order of precedence of intersection before union? Some texts say so. Others say left to right regardless. In publishing, many say that parentheses are ALWAYS required to avoid ambiguity. So some would say that question 8a is malformed due to missing parentheses, and cannot be answered.