Can Inequality with Factorial Be Proven without Induction?

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cupcakes
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Homework Statement


[itex]\frac{1^2*3^2*5^2...(2n-1)^2}{2^2*4^2*6^2...(2n)^2}<\frac{1}{2n+1}[/itex]

Edit: Must be proven without using induction.

Homework Equations


The Attempt at a Solution


I understand the LHS is the same thing as

[tex]\frac{(2n-1)!}{(2n)!}[/tex]

And (2n)! = [itex]k!2^k[/itex] & (2n-1)! = [itex]\frac{(2k)!}{k!2^k}[/itex]

I've tried substituting and it doesn't seem to help. Any ideas? Thanks.
 
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I was able to prove this by induction, try it out!
 
cupcakes said:

Homework Statement


[itex]\frac{1^2*3^2*5^2...(2n-1)^2}{2^2*4^2*6^2...(2n)^2}<\frac{1}{2n+1}[/itex]

Homework Equations


The Attempt at a Solution


I understand the LHS is the same thing as

[tex]\frac{(2n-1)!}{(2n)!}[/tex]

And (2n)! = [itex]k!2^k[/itex] & (2n-1)! = [itex]\frac{(2k)!}{k!2^k}[/itex]

I've tried substituting and it doesn't seem to help. Any ideas? Thanks.
There are some typos there.

[itex]\displaystyle (2k)!=k!2^k[/itex]

[itex]\displaystyle (2k-1)!=\frac{(2k-1)!\ (2k)!}{(2k)!}=\frac{(2k)!}{k!2^k}[/itex]
 
scurty said:
I was able to prove this by induction, try it out!
I forgot to mention that the problem states that it must be proven without using induction. :(

SammyS said:
There are some typos there.

[itex]\displaystyle (2k)!=k!2^k[/itex]

[itex]\displaystyle (2k-1)!=\frac{(2k-1)!\ (2k)!}{(2k)!}=\frac{(2k)!}{k!2^k}[/itex]

Thanks Sammy :smile:
Does anyone have any other idea or hint that does not involve induction?