can anybody share on me how to find the nth term of a binomial expansion / theorem with the negative exponet

(x+y)^-2,, find the 9th term.. how is it possible?

thanks

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- Sep 20th 2012, 09:31 AMrcsnth term of binomial expansion with negative exonent
can anybody share on me how to find the nth term of a binomial expansion / theorem with the negative exponet

(x+y)^-2,, find the 9th term.. how is it possible?

thanks - Sep 20th 2012, 11:15 PMjohnsomeoneRe: nth term of binomial expansion with negative exonent
I don't think what you're looking for exists.

There is this: For .

So if , then , where (Note ).

You could expand that out, giving:

And then collect all like terms - if it even converges term-wise when you try that (I don't know), much less converges to the original value. So, you could maybe give this approach a whirl - no guarantees from me that it gets you anywhere though. And it puts you in a world of series and convergence - a bit different than the nice formula for the binomial coefficients. I don't think the thing you want exists. - Sep 21st 2012, 01:47 AMa tutorRe: nth term of binomial expansion with negative exonent
Maybe and then expand to get