1. The problem statement, all variables and given/known data The question requires me to approximate binomial distribution to get poisson distribution. Show that N!/(N-n)!=N^n. 2. Relevant equations N!/n!(N-n)! p^n q^(N-n)=Binomial distribution 3. The attempt at a solution I expanded N!/(N-n)! and got: (N-1)(N-2)(N-3)....(N-n+2)(N-n+1). This didn't help me in getting the required approximation. So, then I wrote it as follows:( N-(n-(n-1)) ) ( N-( n- (n-2) ) )...( N-(n-2) ) ( N-(n-1) ). It seem to have further complicated the question. A little help please. Thank you.