在等差數(shù)列

中,公差為

,且

,則

等于
A. | B.8 | C. | D.4 |
分析:利用等差數(shù)列的前n項和公式將已知條件S
10=4S
5表示成首項與公差,求出

的值.
解:因為S
10=4S
5,
所以10a
1+

d=4(5a
1+

d)
即2a
1=d
∴

=

故選C.
練習(xí)冊系列答案
相關(guān)習(xí)題
科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分12分)
已知各項均為正數(shù)的數(shù)列

的前
n項和

滿足


(1)求數(shù)列

的通項公式;
(2)設(shè)數(shù)列

為數(shù)列

的前
n項和,求證:

查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
已知等差數(shù)列1,

,等比數(shù)列3,

,則該等差數(shù)列的公差為
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:填空題
已知數(shù)列

的前4項和等于4,設(shè)前n項和為

,且

時,

,則
.
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:填空題
設(shè)數(shù)列

的前

項和

滿足:

,

,則通項

=
.
查看答案和解析>>