摘要：Chapter 1 Real and Complex Number Systems INTRODUCTION A satisfactory discussion of the main concepts of analysis (such as convergence, continuity, differentiation, and integration) must be based o... 阅读全文

摘要：#多项式定理 --- #瓮模型Urn --- $n$个瓮里各有一个球，各个球不同，从中取出$k$个球，则有几种取法（$k$个球是有排列的）？ 回忆： case1: 每次取出后放回去，由乘法原理，每次取，都有$n$种情况, $n^k$ case2: 每次取出后不放回去， $$\begin{align*}n(n-1)(n-2)\text{...}(n-k)\tag{1}\end{align*}$$... 阅读全文