满分5 >
高中数学试题 >
从集合{1,2,3,5,7,-4,-6,-8}中任取三个不同的元素,分别作为方程...
从集合{1,2,3,5,7,-4,-6,-8}中任取三个不同的元素,分别作为方程Ax2+By2=C中的A、B、C的值,则此方程表示双曲线的概率为 .
考点分析:
相关试题推荐
已知1是a
2,b
2的等比中项,又是
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924052_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924052_ST/1.png)
的等差中项,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924052_ST/2.png)
的值是
.
查看答案
请阅读下列材料:若两个正实数a
1,a
2满足a
12+a
22=1,那么a
1+a
2![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924051_ST/0.png)
.证明:构造函数f(x)=(x-a
1)
2+(x-a
2)
2=2x
2-2(a
1+a
2)x+1,因为对一切实数x,恒有f(x)≥0,所以△≤0,从而得4(a
1+a
2)
2-8≤0,所以a
1+a
2![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924051_ST/1.png)
.根据上述证明方法,若n个正实数满足a
12+a
22+…+a
n2=1时,你能得到的结论为
.
查看答案
已知角α终边上一点P(-4,3),求
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924050_ST/0.png)
的值.
.
查看答案
观察下列等式:观察下列等式:
C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/0.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/1.png)
=2
3-2,
C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/2.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/3.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/4.png)
=2
7+2
3,
C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/5.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/6.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/7.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/8.png)
=2
11-2
5,
C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/9.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/10.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/11.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/12.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/13.png)
=2
15+2
7,
…
由以上等式推测到一个一般结论:
对于n∈N
*,C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/14.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/15.png)
+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/16.png)
+…+C
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924049_ST/17.png)
=
.
查看答案
已知函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024180248775592434/SYS201310241802487755924048_ST/0.png)
,若方程f(x)=0有3个不等的实根,则实数a的取值范围是
.
查看答案