factorials

im not sure if this is trig or precal. for factorial a_n = (2n)! what does a_n+1 = ?
i thought you just add 1 to the end and get (2n+1)! but its not...

Quote:

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Originally Posted by jeph

im not sure if this is trig or precal. for factorial a_n = (2n)! what does a_n+1 = ?
i thought you just add 1 to the end and get (2n+1)! but its not...

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I'll assume that we are after a_{n+1}, so we have:

a_n = (2n)!

so:

a_{n+1} = (2(n+1))! = (2n+2)!

RonL

Quote:

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Originally Posted by jeph

im not sure if this is trig or precal. for factorial a_n = (2n)! what does a_n+1 = ?
i thought you just add 1 to the end and get (2n+1)! but its not...

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a_n = (2n)!

a_n+1 = (2(n+1))! = (2n + 2)!


EDIT: You're too quick for me Captain!