Tn=4*2^1+7*2^2.(3n+1)*2^n 2Tn=4*2^2+7*2^3.(3n-2)*2^n+(3n+1)*
Tn=3×20+7×2+…+(4n-1)•2n-1
n大于等于3,Tn=3-(n+3)(1/2)的n次方,比较Tn和5n/(2n+1)大小并证明
已知Cn=(3n-1)2/3^n,n=1,2,3,…,Tn为数列{Cn}的前n项和,求Tn
数列bn的前n项和为Tn,6Tn=(3n+1)bn+2,求bn
已知Sn=1/2n(n+1),Tn=S1+S2+S3+.+Sn,求Tn.
求数列Cn=2^n(2n-1)的前n项和Tn=2*1+4*3+8*5+…+2^n(2n-1)
{an}{bn}为等差数列,前n项和分别为Sn,Tn,(1)S(2n+1)/Tn=2n+1/n+4 求a10/b5(2)
有关等差数列的数学题已知等差数列{an},{bn}的前n项和分别为Sn,Tn,且Sn/Tn=(3n+2)/(2n+1),
若{an}{bn}等差,其前n项和分别为Sn Tn若Sn/Tn=2n+3/3n-1
两个等差数列{an}和{bn}的前n项和分别是Sn和Tn,Sn/Tn=2n+3/3n-1,求a9/b9
两个等差数列{an}和{bn}的前n项和分别是sn和tn,若sn/tn=(2n+3)/(3n-1),求a9/b9
1.两个等差数列{an}和{bn}的前n项和分别是Sn,Tn,若Sn/Tn=2n+3/3n-1,求a9/b9.