来自高小雅的问题
casiofx-991怎么算组合数?
casiofx-991怎么算组合数?
1回答
2020-02-04 19:28
casiofx-991怎么算组合数?
casiofx-991怎么算组合数?
我的是991ESPLUS.
应该是这样的,排列和组合是×和÷的第二功能,"nPr"为n个数中取r个全排列,"nCr"为n个数中取r个组合.
排列,例如5个数取2个全排列:"5","SHIFT","×","2","=".结果为20=5×4=5!/(5-2)!.
组合,例如5个数取2个组合:"5","SHIFT","÷","2","=".结果为10=5×4/2=5!/((5-2)!2!).
完毕.