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#1 2010-03-03 06:58:50

White_Owl
Member
Registered: 2010-03-03
Posts: 106

simplification of factorials?

I am working Rosen's book. Problem 4.1#6:
Prove that


whenever

I am supposed to do it by using induction, so my basis step is:


And the inductive step is (for n+1):

And now I am completely stuck.
Please, point me to the right direction on how to simplify those factorials?

Last edited by White_Owl (2010-03-03 06:59:36)

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#2 2010-03-03 10:33:43

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: simplification of factorials?

The inductive step should be

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#3 2010-03-03 10:44:23

White_Owl
Member
Registered: 2010-03-03
Posts: 106

Re: simplification of factorials?

Oh! I think I got it.
You replaced the

with
because it is the inductive hypothesis...

Arrrr... it is so .... not straight-forward sad

Last edited by White_Owl (2010-03-03 10:51:29)

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#4 2010-03-03 10:58:16

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: simplification of factorials?

White_Owl wrote:

it is so .... not straight-forward sad

Yes, it is. You just need to get used to the trick. smile

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#5 2010-03-03 11:25:10

LQ
Real Member
Registered: 2006-12-04
Posts: 1,285

Re: simplification of factorials?

I never learnt the trick of x! magic but I'll learn some day. To grasp that... Painfull.


I see clearly now, the universe have the black dots, Thus I am on my way of inventing this remedy...

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