If upper-case and lower-case letters are considered as different letters,how many six-letter computer passwords are possible
a) with no repeated letters?
b) with at least one capital letters?
Thanks in advance!
怎么解这道题?谢谢!
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回复:怎么解这道题?谢谢!
-xum57-
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01/11/2009 postreply
14:46:49
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回复:回复:怎么解这道题?谢谢!
-月明人倚楼-
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01/12/2009 postreply
17:25:21
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回复:怎么解这道题?谢谢!
-月明人倚楼-
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(287 bytes)
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01/12/2009 postreply
20:07:20
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P(52,6)-P(26,6)= 14492368800正确,谢谢!
-xum57-
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(39 bytes)
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01/13/2009 postreply
12:03:41