E Content ( Sets )

 Class XI - Chapter 1

Sets

Learning outcomes 

• Learner will be able to provide examples for sets

• Learner will be able to identify sets from their set- builder form 

• Learner will be able to differentiate finite sets and infinite sets

Note

Definition:

A set is a well-defined collection of distinct objects, called elements or members.

Examples:

Set of vowels in English: {a, e, i, o, u}

Set of even natural numbers: {2, 4, 6, 8, …}

Roster Form:

In this form, elements are listed within curly brackets.

Example: {1, 3, 5, 7}

Set-Builder Form:

In this form, a set is described by a property its elements satisfy.

Example: {x | x is an odd number less than 10}

Finite sets:

A set with a countable number of elements.

Example: {2, 4, 6, 8}

Infinite Set:

A set with uncountable or endless elements.

Example: {1, 2, 3, 4, …} (natural numbers)

Examples:

Video of the class 

https://youtu.be/yOzzfO-46k4?si=7oiNEQNsrhjErgaE

Self assessment questions

Question 1:

Write the set of all vowels in the English alphabet using:

(a) Roster form

(b) Set-builder form

Question 2:

Identify whether the following set is finite or infinite:

A = {x | x is a natural number greater than 10}