满分5 >
高中数学试题 >
在(x-a)10的展开式中,x7的系数是15,则实数a= .
在(x-a)10的展开式中,x7的系数是15,则实数a= .
考点分析:
相关试题推荐
若x、y∈{x|x=a
+a
1•10+a
2•100},其中a
i∈{1,2,3,4,5,6,7}(i=0,1,2),且x+y=636,则实数对(x,y)表示坐标平面上不同点的个数为( )
A.50个
B.70个
C.90个
D.180个
查看答案
已知函数f(x)=|log
2|x-1||,且关于x的方程[f(x)]
2+af(x)+b=0有6个不同的实数解,若最小实数解为-3,则a+b的值为( )
A.-3
B.-2
C.0
D.不能确定
查看答案
已知P是椭圆
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/0.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/1.png)
=1上的一点,F
1、F
2是该椭圆的两个焦点,若△PF
1F
2的内切圆半径为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/2.png)
,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/3.png)
的值为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/4.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/5.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966007_ST/6.png)
D.0
查看答案
①若ξ~
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966006_ST/0.png)
,则Eξ=1;②若ξ~N(2,4),则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183557596396656/SYS201310241835575963966006_ST/1.png)
~N(0,1);③在某项测量中,测量结果ξ服从正态分布N(1,σ
2)(σ>0),若ξ在(0,2)内取值的概率为0.8,则ξ在(0,1)内取值的概率为0.4.其中正确的命题是( )
A.①②
B.②③
C.①③
D.①②③
查看答案