lim[2^(2n-1)-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]=1 则a=1/2
lim[2^(2n-1)-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]
=lim[(2^2n)/2-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]
=lim[1/2-a*3^(n+1)/2^2n]/[3^(n+1)/2^(2n)+a]
=(1/2-0)/(0+a)
=1
a=1/2
lim[2^(2n-1)-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]=1 则a=1/2
lim[2^(2n-1)-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]
=lim[(2^2n)/2-a*3^(n+1)]/[3^(n+1)+a*2^(2n)]
=lim[1/2-a*3^(n+1)/2^2n]/[3^(n+1)/2^(2n)+a]
=(1/2-0)/(0+a)
=1
a=1/2