DM-11-Derangements

Here you learn how to calculate derangements

[dusko]

Thank you sir, you are very good teacher and everything is clear without doubts.

[bhavuks]

Sir I have a confusion, how non relative prime numbers = pq + p^2 - p ?

[arundhakad]

Why you have not covered Recurrence Relations and Generating functions

[saddamahmad]

Thankyou sir your video is very helpful to us

again very very thanks a lot for helping us

[ayushgoel]

Sir, How to solve recurrence relation videos are missing !!!

[anchitjindal]

Number of non derrangements when 4 persona are in their original position should be zero because when 4 persons have occupied their original position their will be only one position left which is correct position of 5th person. So there will be zero non derrangements. Please correct if I am wrong

[tulasiram]

@10.35 when 1, 2, 3, 4 are in exact positions, then the last element has to be in the correct position only, which is the given sequence, in one way only

[bense_tony]

Important Rule :
If the clockwise and counter clockwise orders CAN be distinguished then total number of circular permutation of n elements taken all together = (n-1)!
If the clockwise and counter clockwise orders CANNOT be distinguished then total number of circular permutation of n elements taken all together = (n-1)! / 2

[akumlonglongkumer]

someone pls prove me non relative prime numbers=pq+p^2-p i think the prove vedio got cut here

[ranjeet]

the main question is why the signs are alternating ?

[muhammadiqbalbazmi]

sir voice is not clear in this video.
anyway thanks.