回複：嚴格求解: 0.4833716386560448

您少了:2,2,1,1,1; 2,2,2,1; 3,2,1,1; 3,3,1; 4,2,1; 4,3.
一般用1-P(30,7)/30^7為好.手算都可以.

所有跟帖： 

• 回複：回複：嚴格求解: 0.4833716386560448 -芷娞- ♀ (16 bytes) () 05/08/2010 postreply 15:24:36

• You are right! I am a mathmatician and statistician -noname100- ♂ (0 bytes) () 05/14/2010 postreply 17:00:16