Tnad Posted April 30, 2010 Share Posted April 30, 2010 Can you explain how? how can 0!=1 and 1!=1 Thanx Link to comment Share on other sites More sharing options...
the tree Posted April 30, 2010 Share Posted April 30, 2010 Intuitively: how many ways do think there are to order zero objects? Slightly less intuitively: [math]n! = n (n-1)![/math] [math]1! = 1 \cdot 0![/math] [math]0! = \tfrac{1!}{1} = 1[/math] Really: that's just the definition. Link to comment Share on other sites More sharing options...
Tnad Posted May 1, 2010 Author Share Posted May 1, 2010 Thank you, the tree. I get it now. Link to comment Share on other sites More sharing options...
the tree Posted May 3, 2010 Share Posted May 3, 2010 Oh I just thought, it's worth mentioning that the factorial function can be generalised to the Gamma function. [imath]n! = \Gamma(n+1)[/imath] where [imath]\Gamma(z) := \int_0^\infty t^{z-1} e^{-t}\,dt[/imath]. And you should be able to verify that [imath]\Gamma(1)=\Gamma(2)=1[/imath] if you're okay with integration by parts. Link to comment Share on other sites More sharing options...
Tnad Posted May 3, 2010 Author Share Posted May 3, 2010 Right.I'm okey with integration by parts but I didn't know about the extension of the factorial function.Thanx,again! Link to comment Share on other sites More sharing options...
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