Mathematical Induction Question

AI Thread Summary
The discussion focuses on finding a simplifying expression for the product (1-1/2^2)(1-1/3^2)...(1-1/n^2) and verifying its validity for integers n ≥ 2. Participants suggest starting by writing out terms to identify patterns, noting that each term can be expressed as (n^2-1)/n^2. It is highlighted that n^2-1 factors into (n-1)(n+1), which allows for cancellation between numerators and denominators in the product. There is uncertainty about using sigma notation, but the approach of examining specific terms is encouraged. The conversation emphasizes the importance of understanding the simplified expression to verify its correctness.
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Find a simplifying expression for the product
(1-1/2^{2})(1-1/3^{2})...(1-1/n^{2})
and verify its validity for all integers n \geq 2

I know how to do the second part of the question, but no idea how to approach the simplifying of the expression. Any tips?
 
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I'm afraid I can't help you with an exact answer, but perhaps you could apply sigma in this situation?

I'm not positive though, so please don't go all out with sigma, there's a high chance that I'm wrong. Hopefully one of the geniuses on this site will be along shortly to help you more!
 
I am puzzled as to how you can do the second part of the problem (verify that the given expression is equal to the simplified expression) without knowing what the simplified expression is!

If I were looking for a simplified expression, I think I would start by writing out a few terms: (1- 1/4)(1- 1/9)(1- 1/16)...= (3/4)(8/9)(15/16)... which makes it easy to see that each term is of the form (n2-1)/n2. Furthermore n2- 1= (n-1)(n+1) so we should be able to cancel each numerator with part of the previous and next denominator.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Essentially I just have this problem that I'm stuck on, on a sheet about complex numbers: Show that, for ##|r|<1,## $$1+r\cos(x)+r^2\cos(2x)+r^3\cos(3x)...=\frac{1-r\cos(x)}{1-2r\cos(x)+r^2}$$ My first thought was to express it as a geometric series, where the real part of the sum of the series would be the series you see above: $$1+re^{ix}+r^2e^{2ix}+r^3e^{3ix}...$$ The sum of this series is just: $$\frac{(re^{ix})^n-1}{re^{ix} - 1}$$ I'm having some trouble trying to figure out what to...
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