首页
已知数列{an}满足a1=2,nan+1=(n+1)an+2n(n+1)(Ⅰ)证明:数列{...
试题详情
已知数列{a
n}满足a
1=2,na
n+1=(n+1)a
n+2n(n+1)
(Ⅰ)证明:数列{
}为等差数列,并求数列{a
n}的通项;
(Ⅱ)设c
n=
,求数列{c
n•3
n-1}的前项和T
n.
相关试题
-
已知数列{an}满足a1=2,nan+1=(n+1)an+2n(n+1)
(Ⅰ)证明:数列{}为等差数列,并求数列{an}的通项;
(Ⅱ)设cn=,求数列{cn•3n-1}的前项和Tn.
-
已知数列{an},{bn}满足:a1=3b1=3,a2=6,bn+1=2bn-2n,bn=an-nan-1(n≥2,n∈N*).
(I)探究数列是等差数列还是等比数列,并由此求数列{bn}的通项公式;
(II)求数列{nan}的前n项和Sn.
-
已知数列{an},{bn}满足:a1=3b1=3,a2=6,bn+1=2bn-2n,bn=an-nan-1(n≥2,n∈N*).
(I)探究数列是等差数列还是等比数列,并由此求数列{bn}的通项公式;
(II)求数列{nan}的前n项和Sn.
-
已知数列{an},{bn}满足:a1=3b1=3,a2=6,bn+1=2bn-2n,bn=an-nan-1(n≥2,n∈N*).
(I)探究数列是等差数列还是等比数列,并由此求数列{bn}的通项公式;
(II)求数列{nan}的前n项和Sn.
-
已知数列{an}的前n项和Sn满足S2=3,2Sn=n+nan,n∈N*.
(1)求{an}的通项公式,并求数列{2n-1•an}的前n项和Tn;
(2)设,证明:…+.
-
(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;
(2)求an;
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn.
-
(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;
(2)求an;
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn.
-
已知数列{an}中,a1=1,nan+1=2(a1+a2+…+an)
(1)求a2,a3,a4;
(2)求数列{an}的通项an;
(3)设数列{bn}满足,证明:①(; ②bn<1.
-
已知数列{an}中,a1=1,nan+1=2(a1+a2+…+an)
(1)求a2,a3,a4;
(2)求数列{an}的通项an;
(3)设数列{bn}满足,证明:①(; ②bn<1.
-
已知数列{an}中,a1=1,nan+1=2(a1+a2+…+an)
(1)求a2,a3,a4;
(2)求数列{an}的通项an;
(3)设数列{bn}满足,证明:①(; ②bn<1.