Set Theory:
The set which does not contain any element is known as an empty set or a null set.
If every point of set A belongs to B then A is contained or included in B & called suset of B.
B is called trhe superset of a.This is represented as A ⊂ B or B ⊃ A
Two sets are identical,if they contain exactly same points and is then denoted as A = B.Another way to represent this is
A = B if and only if A ⊂ B or B ⊂ A
Operation with Sets:
The union of two sets A and B (A ∪ B) is the set of points which belongs to atlease one of them.
The intersection of two sets A and B (A ∩ B) is the set of points which belongs to both of them.
Sets obey commutative law od union and intersection.
A ∪ B = B ∪ A ; A ∩ B = B ∩ A
Sets obey associative law of union and intersection
(A ∪ B) ∪ C = A ∪ (B ∪ C)
(A ∩ B) ∩ C = A ∩ (B ∩ C)
Sets obey distributive law of union and intersection
(A ∪ B) ∩ C = (A ∩ C) ∪ (B ∩ C)
(A ∩ B) ∪ C = (A ∪ C) ∩ (B ∪ C)
De Morgan's Law:
(A ∪ B)c = Ac ∩ Bc
(A ∩ B)c = Ac ∪ Bc
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