回复:details? please!
jinjing
2010-04-16 16:00:53
( reads)
I use graph doing this question.6 is spacial,it should be between in the 1and 5.We get 5! If 6 out get new and cancel
cases are the same.Put 2,4 together 1,5,3 and 24 ,we have 2*4!cases should be canceled....Thank you.
皆兄弟也
2010-04-16 20:55:592*4!可以理解,5!仍不太明白。anyway, thank you!