Question

排列组合,字母“C”右上角1右下角3,乘“C”右上角2右下角4,乘“C”右上角1右下角4,怎么计算?我所有分数了!

Answer 1

参考你的写法：

(“C”右上角1右下角3)=3/1=3

(“C”右上角2右下角4)=(4*3)/(1*2)

(“C”右上角1右下角4)=4/1

(“C”右上角1右下角3)*(“C”右上角2右下角4)*(“C”右上角1右下角4)

=3*[(4*3)/(1*2)]*4

=72

通常:

(“C”右上角n右下角m) (m≥n)

=[m*(m-1)*(m-2)*...*(m-n)]/[1*2*3*...*n]

仅供参考!