According to the conditions of our project, we have to choose two topics of interest for us. One of our interest will be set A, the other will be set B.
I pick A = women, B = physics. These sets may overlap, because there are some women physicians exist.
- I follow the instructions and obtain 16 books by using search tools (keywords: “women AND physics”)
- For example, one book I have found is named “Women in chemistry and physics : a biobibliographic sourcebook” Westport, Conn. : Greenwood Press, 1993.
- This book belongs to region II of our Venn diagram. This is because this book is about women and about physics (at the same time).
- AND give us the intersection of two sets, because only books about women and physics are shown. If a book is about women, but not about physics, it will not be shown. If a book is about physics, but not about women, it will not be shown too. Hence, a book is shown only when it belongs to both sets – and this is the intersections of two sets.
Now we do a new search with keywords “Women OR physics”
- I found 3986 books in this search.
- OR gives us the union of both sets. The result is shown for all books about women plus all books about physics (including books about both women and physics).
Now we search separately – for physics, for women:
- Set A = women - 3672 books.
- Set B = physics – 330 books.
- The result is really fits the formula:
nA∪B=3986
nA=3672
nB=330
nA∩B=16
3986=3672+330-16
The last expression is an identity. Hence, the formula is true.
- First reason: the book is about physics. Second reason: the book is NOT about women
- First reason: the book is NOT about physics. Second reason: the book is NOT about women
