α+β=A(n+1)/An
αβ=1/An
6(α+β)=2αβ+3
6A(n+1)/An=2/An+3
6A(n+1)=3An+2
6A(n+1)-4=3An-2
2[3A(n+1)-2]=3An-2
[3A(n+1)-2]/[3An-2]=1/2 等比
C(n+1)=3A(n+1)-2
Cn=3An-2
c1=3A1-2=3/2
Cn=3/2*(1/2)^(n-1)=3*(1/2)^n=3An-2
An=(1/2)^n+2/3
α+β=A(n+1)/An
αβ=1/An
6(α+β)=2αβ+3
6A(n+1)/An=2/An+3
6A(n+1)=3An+2
6A(n+1)-4=3An-2
2[3A(n+1)-2]=3An-2
[3A(n+1)-2]/[3An-2]=1/2 等比
C(n+1)=3A(n+1)-2
Cn=3An-2
c1=3A1-2=3/2
Cn=3/2*(1/2)^(n-1)=3*(1/2)^n=3An-2
An=(1/2)^n+2/3