Re: - - Proof by mathematical induction
- From: Bill Dubuque <wgd@xxxxxxxxxxxxxxxxxxxx>
- Date: 29 Sep 2009 15:36:37 -0400
Tim Little <tim@xxxxxxxxxxxxxxxxxx> wrote:
On 2009-09-29, qsymmetry <qsymmetry@xxxxxxxxx> wrote:
For each natural n, let f(n) = (n^2 + n + 1)^2 + 1 and let
P_n = [ f(1) f(3) ... f(2n - 1)]/ [f(2) f(4) ... f(2n)]
I would like to show that P_1 + .. + P_n < 1/2 for each n.
I've shown that P_1 and P_1 + P_2 < 1/2; and I also noticed that
f(2n - 1)/f(2n) < 1
but I don't see how this observation helps in proving the above
inequality.
It doesn't. However, the expression for P_n in terms of n simplifies
surprisingly well,
HINT f(n) = g(n) g(n+1) so multiplicative telescopy ensues
and the inequality should be much easier to prove from the simplified form.
.
- References:
- - - Proof by mathematical induction
- From: qsymmetry
- Re: - - Proof by mathematical induction
- From: Tim Little
- - - Proof by mathematical induction
- Prev by Date: Re: Two finite sequences
- Next by Date: newbie question
- Previous by thread: Re: - - Proof by mathematical induction
- Next by thread: Re: - - Proof by mathematical induction
- Index(es):
Relevant Pages
|