Preparing

摘要： \[展开式:C_{n}^{m} = \frac{A_{n}^{m}}{A_{m}^{m}} = \frac{n(n-1)(n-2)...(n-m+1)}{m!} \quad(m \ll n) \]\[\\ \\ \]\[阶乘式:C_{n}^{m} = \frac{n!}{m!(n-m)!} \qua 阅读全文