How sets are expressed
- Roster method or Tabular method: The elements of
the set are listed explicitly, separated by commas and enclosed in
curly braces.
Example: A={1,2,3,4} and B={a,b,c}.
For sets with more elements, show the first few entries to display a
pattern, and use an ellipsis to indicate “and so on.”
For example: {1,2,3,4,5…,20}
- Set Builder Notation: Used to describe infinite
sets or when the set has numeros elements.
Example: N={x∈Z∣x>0}.
Here, the vertical bar , is read
as “such that” or “for which.” Hence, the right-hand side of the
equation is pronounced as “the set of x belonging to the set of
integers such that x>0,” or simply “the set of integers x such that
x>0.” In general, this descriptive method appears in the format {x|
condition that is satisfied by x}. Example
A={x∣x is an even integer}
B={x∣x>0} (Set of all positive numbers)