What are relations? | Relations and Functions | Grade 11 | Math | Khan Academy

Using what we know about ordered pairs, and cartesian product of sets, we finally define what a relation is between two sets. We use an example of two sets: one containing living beings and the other containing places to live. We then define terms related to relations: Domain (set of permissible values of input), Range (set of possible values of output) and Codomain (set of permissible values of output). We then touch upon the concept of image (elements from second set) and pre-image (elements from first set). We finally learn how to write relations in set-builder form and roster form. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! (https://www.khanacademy.org/math/ncer...) Timestamps: 00:00 A beautiful example (living beings and places to live) 02:31 Mathematical definition of a relation 02:52 Defining Domain, Range, Codomain (with examples) 04:43 Defining Image and Pre-image 05:19 Set builder and Roster form (representing relations) Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Ashish Gupta