Uploaded November 2024 | Updated September 2026, 1 week ago
!!this is not a factorial
You have read that wrong, this is not 7 factorial but 7 bang!! Here I calculate the number of derangements of 7 objects, which is the number of ways of assigning 7 gifts to 7 people in such a way that each person doesn't receive their own gifts. In other words, it's the number of permutations of 7 objects without fixed points. I do it here by using a recursive argument, and in another video I prove this using the inclusion-exclusion principle. Enjoy this fun counting and probability and statistics extravaganza!!
Inclusion-Exclusion way: youtu.be/h-ipp-kx28o (members only for now, but will be published at a later date)
YouTube: youtube.com/drpeyam
Instagram: instagram.com/peyamstagram
Teespring merch: dr-peyam.creator-spring.com/?
!!this is not a factorial
You have read that wrong, this is not 7 factorial but 7 bang!! Here I calculate the number of derangements of 7 objects, which is the number of ways of assigning 7 gifts to 7 people in such a way that each person doesn't receive their own gifts. In other words, it's the number of permutations of 7 objects without fixed points. I do it here by using a recursive argument, and in another video I prove this using the inclusion-exclusion principle. Enjoy this fun counting and probability and statistics extravaganza!!
Inclusion-Exclusion way: youtu.be/h-ipp-kx28o (members only for now, but will be published at a later date)
YouTube: youtube.com/drpeyam
Instagram: instagram.com/peyamstagram
Teespring merch: dr-peyam.creator-spring.com/?
