已知有等比数列{an}和等差数列{bn},且an=2的n次方,bn=2n+1,求数列{an*bn}的前n项和Tn

来源：学生作业帮编辑：搜狗做题网作业帮分类：数学作业时间：2024/06/13 16:59:14

Tn=2*3+5*2^2+7*2^3+...+(2n+1)*2^n
2Tn=3*2^2+5*2^3+7*2^4+...+(2n+1)*2^(n+1)
Tn-2Tn=2*3+2*2^2+2*2^3+...+2*2^n-(2n+1)*2^(n+1)
-Tn=6+2[4*(2^(n-1)-1)/(2-1)]-(2n+1)*2^(n+1)
-Tn=6+4*2^n-8-2(2n+1)*2^n
Tn=(4n-2)*2^n+2

设bn=(an+1/an)^2求数列bn的前n项和Tn an=3*2^(n-1),设bn=n/an求数列bn的前n项和Tn 已知数列{an}是等差数列,a2=6,a5=18;数列{bn}的前n项和是Tn,且Tn+(1/2)bn=1. 已知数列{an}是等差数列,a2=6,a5=18,数列{bn}的前n项和是Tn,且Tn+(1/2)bn 已知数列{an}是等差数列,a2=6,a5=18,数列{bn}的前n项和是Tn,且Tn+(1/2)*bn 已知等差数列{an}满足:a3=7,S11=143 ,令bn=2^an(N属于N*),求数列{bn}的前n项和Tn 已知{an},{bn}均为等差数列,前n项的和为An,Bn,且An/Bn=2n/(3n+1),求a10/b10的值已知等差数列an=2n,等比数列bn=2*3^(n-1)（2乘以3的n减1次方）,设cn=an/bn,求cn前n项和Tn 数列{an}的前n项和为Sn=n平方+n,（1）求an,（2）令bn=2的an次方,证明bn为等比数列,并求前n项和Tn 已知数列an=4n-2和bn=2/4^(n-1),设Cn=an/bn,求数列{Cn}的前n项和Tn 等差数列{an},{bn}的前n项和分别为An,Bn,切An/Bn=2n/3n+1,求lim(n→∞)an/bn 已知数列{an}的前n项和为Sn=2的n-1次方-2 求｛an｝的通项公式an 令bn=2n+an tn是bn的前n项和