已知等比数列{an}满足an>0,n=1,2,……,且a5*a(2n-5)=2^2n,则当n》1时,log2(a1)+lo已知等比数列{an}满足an>0,n=1,2,……,且a5*a(2n-5)=2^2n,则当n》1时,log2(a1)+log2(a3)+…+log2(a(2n-1))=

问题描述:

已知等比数列{an}满足an>0,n=1,2,……,且a5*a(2n-5)=2^2n,则当n》1时,log2(a1)+lo
已知等比数列{an}满足an>0,n=1,2,……,且a5*a(2n-5)=2^2n,则当n》1时,log2(a1)+log2(a3)+…+log2(a(2n-1))=

A5*A(2n-5)=2^(2n)(n≥3)
A1*Q^4 * A1*Q^(2n-6)=2^(2n)
A1^2*Q^(2n-2)=2^(2n)
An=2^n
所以log2(A1)+log2(A3)+……+log2[A(2n-1)]=1+3+……+(2n-1)=n*2n/2=n²