Math again urrrgghh

[nid404]

i found this much easier thank k+1

but this is not linked correctly
why would you simply do it without a reason
as in

[1× 2 × 3 × 4 × 5 × . . . . . . . . (2n - 2) (2n - 1) (2n) ]/ n!

how does 2n!/n! become something like this....no...not getting it

[Ghost Of Highbury]

arre dude...

n! = 1 * 2 * 3 * 4 ......*n rite?

so (2n)! = 1*2*3*4.......2n..

suppose n = 3

n! = 1*2*3 = 6

2n = 6

6! = (2n)! = 1*2*3*4*5*6. = 720..

thats the rule///

[nid404]

I know that.....

but still note getting what is done there