給出定義:在數(shù)列中.都有.則稱為“等方差數(shù)列 .下列是對(duì)“等方差數(shù)列 的判斷: 查看更多

 

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給出定義:在數(shù)列{an}中,都有( p為常數(shù)),則稱{an}為“等方差數(shù)列”.下列是對(duì)“等方差數(shù)列”的判斷:
(1)數(shù)列{an}是等方差數(shù)列,則數(shù)列是等差數(shù)列;
(2)數(shù)列{(-1)n}是等方差數(shù)列;
(3)若數(shù)列{an}既是等方差數(shù)列,又是等差數(shù)列,則該數(shù)列必為常數(shù)數(shù)列;
(4)若數(shù)列{an}是等方差數(shù)列,則數(shù)列{akn}( k∈N*,k為常數(shù))也是等方差數(shù)列.
其中正確命題序號(hào)為   

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給出定義:在數(shù)列{an}中,都有( p為常數(shù)),則稱{an}為“等方差數(shù)列”.下列是對(duì)“等方差數(shù)列”的判斷:
(1)數(shù)列{an}是等方差數(shù)列,則數(shù)列是等差數(shù)列;
(2)數(shù)列{(-1)n}是等方差數(shù)列;
(3)若數(shù)列{an}既是等方差數(shù)列,又是等差數(shù)列,則該數(shù)列必為常數(shù)數(shù)列;
(4)若數(shù)列{an}是等方差數(shù)列,則數(shù)列{akn}( k∈N*,k為常數(shù))也是等方差數(shù)列.
其中正確命題序號(hào)為   

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給出定義:在數(shù)列{an}中,都有
a2n
-
a2n-1
=p(n≥2,    n∈N*)
( p為常數(shù)),則稱{an}為“等方差數(shù)列”.下列是對(duì)“等方差數(shù)列”的判斷:
(1)數(shù)列{an}是等方差數(shù)列,則數(shù)列{
a2n
}
是等差數(shù)列;
(2)數(shù)列{(-1)n}是等方差數(shù)列;
(3)若數(shù)列{an}既是等方差數(shù)列,又是等差數(shù)列,則該數(shù)列必為常數(shù)數(shù)列;
(4)若數(shù)列{an}是等方差數(shù)列,則數(shù)列{akn}( k∈N*,k為常數(shù))也是等方差數(shù)列.
其中正確命題序號(hào)為______.

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(2009•湖北模擬)給出定義:在數(shù)列{an}中,都有
a
2
n
-
a
2
n-1
=p(n≥2,n∈N*)
( p為常數(shù)),則稱{an}為“等方差數(shù)列”.下列是對(duì)“等方差數(shù)列”的判斷:
(1)數(shù)列{an}是等方差數(shù)列,則數(shù)列{
a
2
n
}
是等差數(shù)列;
(2)數(shù)列{(-1)n}是等方差數(shù)列;
(3)若數(shù)列{an}既是等方差數(shù)列,又是等差數(shù)列,則該數(shù)列必為常數(shù)數(shù)列;
(4)若數(shù)列{an}是等方差數(shù)列,則數(shù)列{akn}(k∈N*,k為常數(shù))也是等方差數(shù)列.
其中正確命題序號(hào)為
(1)(2)(3)(4)
(1)(2)(3)(4)

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閱讀下面給出的定義與定理:
①定義:對(duì)于給定數(shù)列{xn},如果存在實(shí)常數(shù)p、q,使得xn+1=pxn+q 對(duì)于任意n∈N+都成立,我們稱數(shù)列{xn}是“線性數(shù)列”.
②定理:“若線性數(shù)列{xn}滿足關(guān)系xn+1=pxn+q,其中p、q為常數(shù),且p≠1,p≠0,則數(shù)列{xn-
q1-p
}
是以p為公比的等比數(shù)列.”
(Ⅰ)如果an=2n,bn=3•2n,n∈N+,利用定義判斷數(shù)列{an}、{bn}是否為“線性數(shù)列”?若是,分別指出它們對(duì)應(yīng)的實(shí)常數(shù)p、q;若不是,請(qǐng)說(shuō)明理由;
(Ⅱ)如果數(shù)列{cn}的前n項(xiàng)和為Sn,且對(duì)于任意的n∈N*,都有Sn=2cn-3n,
①利用定義證明:數(shù)列{cn}為“線性數(shù)列”;
②應(yīng)用定理,求數(shù)列{cn}的通項(xiàng)公式;
③求數(shù)列{cn}的前n項(xiàng)和Sn

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