分析:等差数列{an}的前n项和为Sn,等比数列{bn}的前n项和为Tn,
a1=b1=1,a2+b3=a3,S5=5(T3+b2),
设an=1+(n-1)d,bn=q^(n-1),
有b1=1,b3=a3-a2=d,
因为S5=5(T3+b2),S5=5a3,T3=b1+b2+b3=1+b2+d,
所以5a3=5(1+b2+d+b2),得到5a3-5(1+d)=5(a3-1)-5d=10b2,
又因为a3-a1=a3-1=2d,代人得到b2=1/2d,
有b1=1,b2=1/2d,b3=d,
所以公比q=b2/b1=b3/b2,所以d/2=2,得到d=4,q=2,
{an}:an=1+4(n-1)=4n-3,Sn=(2n-1)n;
{bn}:bn=2^(n-1),Tn=2^n-1;
(2)b1/(T1*T2)+b2/(T2*T3)+......bn/(Tn*Tn+1)
=1/1*3+2/3*7+4/7*15+......
=1/2*[(1-1/3)+(1/3-1/7)+(1/7-1/15)+........]
=1/2*{1-1/[2^(n+1)-1]}
1、可设an=1+(n-1)d,bn=1*q^(n-1)=q^(n-1);
a2+b3=1+d+q^2=a3=1+2d,d=q²;
S5=(1+1+4d)*5/2=5(T3+b2)=5(1+q+q²+q)=5(1+q)²=5(1+2d),
(1+q)²=(1+2q²),q²-2q=0,q=2(q=0舍去);
d=q²=4;
an=1+4(n-1)=4n-3,
bn=2^(n-1)
2、bn/(Tn*Tn+1)=2^(n-1)/[(1-2^n)/(1-2)*(1-2^n+1)/(1-2)]
=2^(n-1)/(1-2^n)*(1-2^(n+1))=1/2*【1/(2^n-1)-1/(2^(n+1)-1)】
b1/(T1*T2)+b2/(T2*T3)+......bn/(Tn*Tn+1)=1/2*【1-1/3+1/3-1/7+1/7-1/15+…+1/(2^(n-1)-1