a(n+1)=3an +1a(n+1)+ 1/2=3an+ 3/2=3(an +1/2)[a(n+1) +1/2]/(an +1/2)=3,为定值.a1+ 1/2=1/2 +1/2=1数列{an +1/2}是以1为首项,3为公比的等比数列.an +1/2=1×3^(n-1)=3^(n-1)an=3^(n-1)+1/2数列{an}的通项公式为...