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permutation
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- Posts:1
- Joined:Sat Feb 13, 2016 10:42 pm
here onushiddhanto 2 keno n factorial/n - r factorial ??
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- Posts:1007
- Joined:Sat Dec 09, 2017 1:32 pm
Re: permutation
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.☺☺☺