满分5 >
高中数学试题 >
“a=3”是“直线ax+2y+3a=0和直线3x+(a-1)y=a-7平行”的(...
“a=3”是“直线ax+2y+3a=0和直线3x+(a-1)y=a-7平行”的( )
A.充分不必要条件
B.必要不充分条件
C.充要条件
D.既不充分也不必要条件
考点分析:
相关试题推荐
给定空间中的直线l及平面α,条件“直线l与平面α内无数条直线都垂直”是“直线l与平面α垂直”的( )条件
A.充要
B.充分非必要
C.必要非充分
D.既非充分又非必要
查看答案
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930518264/SYS201311031024209305182000_ST/images0.png)
将正三棱柱截去三个角(如图1所示A,B,C分别是△GHI三边的中点)得到几何体如图2,则该几何体按图2所示方向的侧视图(或称左视图)为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930518264/SYS201311031024209305182000_ST/images1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930518264/SYS201311031024209305182000_ST/images2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930518264/SYS201311031024209305182000_ST/images3.png)
D.
查看答案
设A(x
1,y
1),B(x
2,y
2)是椭圆
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/0.png)
,(a>b>0)上的两点,已知向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/1.png)
=(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/2.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/3.png)
),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/4.png)
=(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/5.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/6.png)
),且
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/7.png)
,若椭圆的离心率
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707021_ST/8.png)
,短轴长为2,O为坐标原点:
(Ⅰ)求椭圆的方程;
(Ⅱ)若直线AB过椭圆的焦点F(0,c),(c为半焦距),求直线AB的斜率k的值;
(Ⅲ)试问:△AOB的面积是否为定值?如果是,请给予证明;如果不是,请说明理由.
查看答案
已知函数f(x)=ax
2+1nx(a∈R).
(I)当
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707020_ST/0.png)
时,求f(x)在区间[1,e]上的最大值和最小值;
(II)如果在公共定义域D上的函数g(x),f
1(x),f
2(x)满足f
1(x)<g(x)<f
2(x),那么就称g(x)为f
1(x)、f
2(x)的“活动函数”,已知函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707020_ST/1.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102420930270746/SYS201311031024209302707020_ST/2.png)
,若在区间(1,+∞)上,函数f(x)是f
1(x)、f
2(x)的“活动函数”,求实数a的取范围.
查看答案
已知圆C:(x-1)
2+y
2=9内有一点P(2,2),过点P作直线l交圆C于A、B两点.
(1)当l经过圆心C时,求直线l的方程;
(2)当弦AB被点P平分时,写出直线l的方程;
(3)当直线l的倾斜角为45°时,求弦AB的长.
查看答案