依题意,可得公比q=2,a1=2,通项an=2^n,所以
原式={lg[2^(n+1)*2^(n+2)*...*2^(2n)]}/n^2
={lg2^[(n+1)+(n+2)+...+(2n)]}/n^2
={[(n+1)+2n]*n/2}*lg2/n^2
当n趋向无穷大时,其极限=3/2*lg2
依题意,可得公比q=2,a1=2,通项an=2^n,所以
原式={lg[2^(n+1)*2^(n+2)*...*2^(2n)]}/n^2
={lg2^[(n+1)+(n+2)+...+(2n)]}/n^2
={[(n+1)+2n]*n/2}*lg2/n^2
当n趋向无穷大时,其极限=3/2*lg2