The probability W(n) that an event characterized by a probability p occurs n times in N trials was shown to be given by the binomial distribution N! W (n) = n!(N n)!P"(1 p)N-n Consider a situation where the probability is small (p 1) and where one is interested in the case n N. Several approximations can be made to reduce this expression to a simpler form. Show that N!/(N n)! - N".