怎麽解這道題？謝謝！

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!

所有跟帖： 

• 回複：怎麽解這道題？謝謝！ -xum57- ♂ (114 bytes) () 01/11/2009 postreply 14:46:49

• 回複：回複：怎麽解這道題？謝謝！ -月明人倚樓- ♂ (54 bytes) () 01/12/2009 postreply 17:25:21

• 回複：怎麽解這道題？謝謝！ -月明人倚樓- ♂ (287 bytes) () 01/12/2009 postreply 20:07:20

• P(52,6)-P(26,6)= 14492368800正確,謝謝！ -xum57- ♂ (39 bytes) () 01/13/2009 postreply 12:03:41