a1>0 q>0,an=a1q^(n-1)>0,数列为正项数列.an=a1×q^(n-1)bn=log2(an)=log2[a1q^(n-1)]=log2(a1)+(n-1)log2(q)b(n+1)=log2(a1)+nlog2(q)b(n+1)-bn=log2(q),为定值.b1=log2(a1)=log2(8)=3数列{bn}是以3为首项,log2(q)...