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Wed 7 Sep, 2005 09:59 pm
Hi all! This one is giving me trouble as well:
Show by mathematical induction that if n is a positive integer, then
(2*n)! < 2^2n*(n!)^2
Here's what I've done so far:
In proving the (n+1)th case I've done this:
(2(n+1))! = (2n+2)!
= (2n+2)*(2n+1)*(2n)!
< (2n+2)*(2n+1)*2^2n(n!)^2 (Using the inductive hypothesis)
< . . .
Now what? I need to get to < [ 2^(2n+2) ] * ((n+1)!)^2 in order for this proof to work.
Any help will be appreciated. Thanks!
If A<B and C<D then AC < BD assuming all are positive.
Make A = (2n)! and B=(2^2n)*(n!)^2
That makes C = (2n+1)(2n+2) and D=4(n+1)^2 if I did the math correctly. C<D, so it works out.
Yeah thanks! I got this one figured out.