Showing posts with label Set theory. Show all posts
Showing posts with label Set theory. Show all posts

Monday, April 8, 2013

How to do Sets in Math

Introduction to do sets in math:

A set is a collection of distinct objects, considered as an object in its own right. Sets are one of the most fundamental concepts in mathematics. Set theory is now a ubiquitous part of mathematics, and can be used as a foundation from which nearly all of mathematics can be derived. Let us see about the concept of how to do sets in math. (Source: Wikipedia)

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Sets in math:


By using two methods we can do the sets in math. They are,

Roster or tabular form
Set-builder form
How to do sets in math by using Roster form:

The elements are separated by using the commas, and the elements are placed inside of braces { }. For example, the set of all odd positive integers less than 8 is expressed in roster form as {1, 3, 5, 7}.

How to do sets in math by using Set-builder form:

For example, in the set {1, 3, 5, 7, 11}, all the elements possess a common property, namely, all are prime number, which are not possessed in any other set. Representing this set by P, we write P = {x: x is a prime numbers in real numbers}


Example problem in set:


Problem1: Find the solution set of the following equation by using roster form x 2 + x – 2 = 0.

Solution:

x 2 + x – 2 = 0 can be expressed as (x – 1) (x + 2) = 0, that is x = 1, – 2.

Therefore, the solution is {1, – 2}.

Problem 2: Find the set {x: x is a positive integer and x2 < 30} in the roster form.

Solution:

By the given we need the following numbers to represent the set -1, 2, 3, 4, 5.

So, the given set in the roster form is {1, 2, 3, 4, 5}.

Problem 3: Find the set A = {1, 4, 9, 16, 25 . . .} by using set-builder form.

Solution:

We may write the set A as A = {x: x is the square of a natural number}

Alternatively, we can write A = {x: x = n2, where n ∈ N}

In this section we have seen about the concept of how to do sets in math.