满分5 >
高中数学试题 >
已知集合A={1,2,3,4,5},B={(x,y)|x∈A,y∈A,x-y∈A...
已知集合A={1,2,3,4,5},B={(x,y)|x∈A,y∈A,x-y∈A},则B中所含元素的个数为( )
A.3
B.6
C.8
D.10
考点分析:
相关试题推荐
已知数列{a
n}的首项
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272020_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272020_ST/1.png)
,n=1,2,3,….
(Ⅰ)证明:数列
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272020_ST/2.png)
是等比数列;
(Ⅱ)求数列
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272020_ST/3.png)
的前n项和S
n.
查看答案
已知数列{a
n}的前n项和s
n满足
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272019_ST/0.png)
(a>0,且a≠1).数列{b
n}满足b
n=a
n•lga
n(1)求数列{a
n}的通项.
(2)若对一切n∈N
+都有b
n<b
n+1,求a的取值范围.
查看答案
设锐角三角形ABC的内角A,B,C的对边分别为a,b,c,a=2bsinA
(Ⅰ)求B的大小;
(Ⅱ)求cosA+sinC的取值范围.
查看答案
已知数列{a
n}满足,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807465127271/SYS201311031028074651272017_ST/0.png)
,n∈N
×.
(1)令b
n=a
n+1-a
n,证明:{b
n}是等比数列;
(2)求{a
n}的通项公式.
查看答案