Can somebody tell me how the denominator contains (2n+2)(2n+1) in the answer. I am thinking (2n)!/(2n+2)! expands into (2n)!/(2n)!(2n+2). This simplifies into 1/(2n+2).

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- May 7th 2010, 06:49 PMp75213Ratio Test for Taylor Expansion of Cosine
Can somebody tell me how the denominator contains (2n+2)(2n+1) in the answer. I am thinking (2n)!/(2n+2)! expands into (2n)!/(2n)!(2n+2). This simplifies into 1/(2n+2).

http://my.thinkwell.com/questionbank...img/215813.gif - May 7th 2010, 07:35 PMRandom Variable
$\displaystyle \frac{(2n)!}{(2n+2)!} = \frac{(2n)!}{(2n+2)(2n+1)(2n)!} $

- May 7th 2010, 08:43 PMp75213
So it is. Many thanks.