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permutation
Posted: Wed Oct 18, 2017 4:48 pm
by abrar fiaz
- werfdsfg.jpg (157.32KiB)Viewed 5303 times
here onushiddhanto 2 keno n factorial/n - r factorial ??
Re: permutation
Posted: Tue Feb 13, 2018 11:30 pm
by samiul_samin
It is just an easy algebric manipulation. because $(n-r)!=n*(n-1)*(n-2)*...2*1$ so the numerator will be$n!$. And we are done.☺☺☺