### SSC 2.SETS (E/M)

Set is a Very easy Chapter In SSC paper -I. so it is my advise to prepare this chapter before all.an you can gain easily marks from this chapter.so in this site u can read and download sets study material free to help students.follow the below instruction and download it.
2.Sets
Key points:
• ·         Set theory was developed by "George Cantor"
• ·         Set: A well defined collection of objects is called set.
• ·         Sets are denoted by capital letters of English, where as elements are denoted   by small letters alphabets of English.
• ·         Sets can be written in the roster form(list form) and the set builder form.
• ·         The symbol for "is belongs to" is "" and "is doesn't belongs to" is "".
• ·         A set which does not contain any element is called an empty set or a null set,or a void  set.
• ·         i)∅ = { } ii) ∅ ≠ { 0 }
• ·         A set is called a finite set if it is possible to count the number of elements of that set.
• ·         A set is called a infinite set if it is not possible to count the number of elements of that set.
• ·         The number of elements in a set is called the cardinal number of the set.
• ·         The universal set is denoted by“ ”.The universal set is usually represented by rectangles.
• ·         ⊂ B & B ⊂ AA = B
• ·         A ∩ B is the set containing only those elements that are common in A & B.
• ·         ∪ B = contains the elements that are either in A or in B or in both.
• ·         A ∩ B = ∅, then A & B are disjoint sets and n(A ∩ B) = 0
• ·         n(A ∪ B) = n(A) + n(B) –n (A ∩ B)
• ·         A & B are disjoint then n(A ∪ B) = n(A) + n(B)     or     n(A∩B)=0
• ·         A-B = {x: x∈ A and x ∉ B}
• ·         Every set is a subset of it self
• ·         Null set is subset of every set.
• ·         If A⊂ BB ⊂ C then A ⊂ C.
• ·         If AB then AUB=B and AB=A.