数列｛an}中,a2=2,a6=0且数列｛1\an+1}是等差数列,则a4等于

数列｛an}中,a2=2,a6=0且数列｛1\an+1}是等差数列,则a4等于
数列｛an}中,a2=2,a6=0且数列｛1\an+1}是等差数列,则a4等于

数列｛an}中,a2=2,a6=0且数列｛1\an+1}是等差数列,则a4等于
1/(a2+1)=1/3,1/(a6+1)=1,所以d=(1-1/3)/4=1/6
1/(a4+1)=1/(a2+1)+2d=2/3,所以a4=0.5