(1)令f(x)=0得x2-6x+6=1,解得x=1或5,由于d>0,所以a1=1,a3=5,2d=4,d=2,
∴an=2n-1(n∈N*)
由于Tn=1-2bn,令n=1得T1=1-2b1,解得b1=
1 |
3 |
2 |
3 |
∴数列{bn}是等比数列,bn=
1 |
3 |
2 |
3 |
(2)由(1)得cn=anbn=(2n-1)?
1 |
3 |
2 |
3 |
2n?1 |
3 |
2 |
3 |
Sn=
1 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
1 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
两式相减得
1 |
3 |
1 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
2n?1 |
3 |
2 |
3 |