、 設(shè)

,

為實數(shù),首項為

,公差為

的等差數(shù)列

的前

項和為

,滿足

.
(1)若

, 求

及

;
(2)求

的取值范圍.(12分)
練習冊系列答案
相關(guān)習題
科目:高中數(shù)學
來源:不詳
題型:解答題
已知數(shù)列

和

的通項公式分別為

,

(

),將集合

中的元素從小到大依次排列,構(gòu)成數(shù)列

。
⑴ 求

;
⑵ 求證:在數(shù)列

中、但不在數(shù)列

中的項恰為

;
⑶ 求數(shù)列

的通項公式。
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
已知數(shù)列

滿足

+

=4
n-3(
n∈

).
(1)若數(shù)列

是等差數(shù)列,求

的值;
(2)當

=2時,求數(shù)列

的前
n項和

;
(3)若對任意
n∈

,都有

≥5成立,求

的取值范圍.
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
(本小題滿分12分)
已知數(shù)列

中,

,

,其前

項和為

,且當

時,

.
(Ⅰ)求證:數(shù)列

是等比數(shù)列;
(Ⅱ)求數(shù)列

的通項公式;
(Ⅲ)令

,記數(shù)列

的前

項和為

,證明對于任意的正整數(shù)

,都有

成立.
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
已知等比數(shù)列

中,公比

若

則

有( )
A.最小值-4 | B.最大值-4 | C.最小值12 | D.最大值12 |
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
已知

,把數(shù)列

的各項排成如下的三角形:記

表示第s行的第t個數(shù),則A(11,12)= ( )

查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
(本題滿分14分)本題共有2個小題,第1小題滿分6分,第2小題滿分8分
已知數(shù)列

是正項等比數(shù)列,滿足

(1)求數(shù)列

的通項公式;
(2)記

是否存在正整數(shù)

,使得對一切

恒成立,若存在,請求出M的最小值;若不存在,請說明理由。
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
(本小題滿分12分)
已知等差數(shù)列{an}中,a1=1,a3=-3.
(I)求數(shù)列{an}的通項公式;
(II)若數(shù)列{an}的前k項和Sk=-35,求k的值.
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
已知等差數(shù)列

滿足

,則

等于( )
A.10 | B.8 | C.6 | D.4 |
查看答案和解析>>