you are right:C(20,4)=C(16+3,3)+C(15+3,3)+...+C(1+3,3)+C(0+3,3)

來源: 皆兄弟也於 2010-09-08 10:09:50 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.