a1=2/3,且满足an=3a(n-1)/[3+2a(n-1)]1/an=[3+2a(n-1)]/[3a(n-1)]=2/3+1/a(n-1)1/an-1/a(n-1)=2/3数列{1/an}是公差为2/3的等差数列a1=2/3 1/a1=3/21/an=1/a1+(n-1)*q=3/2+(n-1)*2/3=(4n+5)/6an=6/(4n+5)...