[理工] 離散 排列組合
[98成大資工]
the number of permutation of the disits 0,1,2,3,4,5 either start
with a 3 or end with a 2.
我的答案是
3 _ _ _ _ _ 加上 _ _ _ _ _ 2 扣掉 3 _ _ _ _ 2 的情形
-> 5! + 5! - 4!
可是答案是
5! + 5! - 2(4!)
^^^
2哪來的= = ?
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推
01/11 01:26, , 1F
01/11 01:26, 1F
→
01/11 01:27, , 2F
01/11 01:27, 2F
→
01/11 01:27, , 3F
01/11 01:27, 3F
→
01/11 01:28, , 4F
01/11 01:28, 4F
推
01/11 01:29, , 5F
01/11 01:29, 5F
→
01/11 01:29, , 6F
01/11 01:29, 6F
→
01/11 01:29, , 7F
01/11 01:29, 7F
→
01/11 01:30, , 8F
01/11 01:30, 8F
→
01/11 01:30, , 9F
01/11 01:30, 9F
→
01/11 01:33, , 10F
01/11 01:33, 10F
→
01/11 01:33, , 11F
01/11 01:33, 11F
→
01/11 01:34, , 12F
01/11 01:34, 12F
→
01/11 01:35, , 13F
01/11 01:35, 13F
→
01/11 08:56, , 14F
01/11 08:56, 14F
→
01/11 11:21, , 15F
01/11 11:21, 15F
推
01/11 18:19, , 16F
01/11 18:19, 16F
推
01/11 19:00, , 17F
01/11 19:00, 17F
推
01/11 19:00, , 18F
01/11 19:00, 18F
→
01/11 19:00, , 19F
01/11 19:00, 19F
→
01/11 19:01, , 20F
01/11 19:01, 20F
→
01/11 19:01, , 21F
01/11 19:01, 21F
→
01/11 19:01, , 22F
01/11 19:01, 22F
→
01/11 19:02, , 23F
01/11 19:02, 23F
→
01/11 19:02, , 24F
01/11 19:02, 24F
→
01/11 19:03, , 25F
01/11 19:03, 25F
推
01/11 21:45, , 26F
01/11 21:45, 26F
→
09/11 14:45, , 27F
09/11 14:45, 27F
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