满分5 >
高中数学试题 >
已知△ABC的一个内角为120°,并且三边长构成公差为4的等差数列,则△ABC的...
已知△ABC的一个内角为120°,并且三边长构成公差为4的等差数列,则△ABC的面积为 .
考点分析:
相关试题推荐
已知
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/1.png)
是夹角为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/2.png)
的两个单位向量,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/3.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/4.png)
-2
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/5.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/6.png)
=k
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/7.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/8.png)
,若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/9.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713008_ST/10.png)
=0,则实数k的值为
.
查看答案
设A
1,A
2,A
3,A
4是平面直角坐标系中两两不同的四点,若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713007_ST/0.png)
(λ∈R),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713007_ST/1.png)
(μ∈R),且
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713007_ST/2.png)
,则称A
3,A
4调和分割A
1,A
2,已知点C(c,0),D(d,O)(c,d∈R)调和分割点A(0,0),B(1,0),则下面说法正确的是( )
A.C可能是线段AB的中点
B.D可能是线段AB的中点
C.C,D可能同时在线段AB上
D.C,D不可能同时在线段AB的延长线上
查看答案
函数y=f(x)在定义域(-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/0.png)
,3)内可导,其图象如图所示.记y=f(x)的导函数为y=f'(x),则不等式f'(x)≤0的解集为( )
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/images1.png)
A.[-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/1.png)
,1]∪[2,3)
B.[-1,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/2.png)
]∪[
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/3.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/4.png)
]
C.[-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/5.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/6.png)
]∪[1,2)
D.(-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/7.png)
,-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/8.png)
]∪[
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/9.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/10.png)
]∪[
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713006_ST/11.png)
,3)
查看答案
设x,y满足约束条件
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713005_ST/0.png)
则目标函数z=x+y的最大值是( )
A.3
B.4
C.6
D.8
查看答案
等差数列{a
n}的通项公式a
n=2n+1,其前n项和为S
n,则数列
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231127065071398/SYS201311012311270650713004_ST/0.png)
前10项的和为( )
A.120
B.70
C.75
D.100
查看答案