两边除以n(n+1)a(n+1)/(n+1)=an/n+2/n(n+1)a(n+1)/(n+1)-an/n=2/n(n+1)=2[1/n-1/(n+1)]a10/10-a9/9=2(1/10-1/11)a9/9-a8/8=2(1/9-1/10)……a2/2-a1/1=2(1/2-1/3)相加a10/10-a1/1=2*(1/2-1/11)=9/11a10=310/11...不对啊，不过还是要谢谢你。o a10/10-a9/9=2(1/9-1/10)a9/9-a8/8=2(1/8-1/9)……a2/2-a1/1=2(1-1/2)相加a10/10-a1/1=2*(1-1/10)=9/5a10=38