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Curated by: Khan Academy India - English (21 videos)
We finally talk about the operator Factorial. We understand its applications and solve some problems involving its simplifications. First we notice factorials, then define it while noting its notation. We then practice identifying and evaluating a few common factorials. After going through some key observations, we practice simplifying expressions and solving equations involving factorials. We finally observe that the formula for rearrangements when all objects are distinct (and also when some objects are similar) contain our beloved factorial! Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! (https://www.khanacademy.org/math/ncert-class-11/xea4762213f311c5e:permutations-and-combinations-ncert-new/xea4762213f311c5e:untitled-900/e/permutations_1) Timestamps: 00:00 Noticing we've been using factorial all along 00:47 Defining factorial and its notation 01:06 Practicing identifying factorials 01:32 Practicing evaluating factorials 02:53 Some key observations for factorials 03:30 Practicing simplifying expressions involving factorials 04:27 Practicing solving equations involving factorials 05:21 Formula for rearrangements when all objects are distinct 06:13 Formula for rearrangements when some objects are similar 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