数列{an}是以a1=4为首项的等比数列,且S3,S2,S4成等差数列

1.2S2=S3+S42S2=S2+A3+S2+A3+A42A3+A4=0A4/A3=-2An=A1×q^n=4×(-2)^(n-1)=(-2)^(n+1)2.|An|=|(-2)^(n+1)|=2^(n+1)Bn=log2|An|=log2(2^(n+1)=n+11/(Bn×B(n+1)=1/((n+1)×(n+1+1))=((n+2)-(n+1))/((n+1)(n+2))=1/(n+...