Question

1*3*5*7*9*11————除以2*4*6*8*10————的极限是多少?

Answer 1

(2n-1)(2n+1)./2^n*n!=(2n-1)2n(2n+1)(2n+2)./(2^n*n!)^2=(2n-1)!/(2^2n*(n!)^2)

lim(2n-1)!/(2^2n*(n!)^2) =sqrt(1/π)