Think And Discuss

1. What is the relation between n(A), n(B), n(A ∩ B) and n(A ∪ B)?

2. If Aand B are disjoint sets, then how can you find n(A ∪ B)?




WHAT WE HAVE DISCUSSED



1. A set is a well defined collection of distinct objects, well defined means that:

(i) There is a universe of objects which are allowed into consideration.

(ii) Any object in the universe is either an element or is not an element of the set.

2. An object belonging to a set is known as an element of the set. We use the symbol 'Î' to denote membership of an element and read belongs to.

3. Sets can be written in the roster form where all elements of the set are written, separated by commas, within curly brackets(braces).

4. Sets can also be written in the set-builder form.

5. A set which does not contain any element is called an empty set, or a Null set, or a void set.

6. A set is called a finite set if its cordinality/ cardinal number is a whole number.



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