设三角形ABC的内角A,B,C的对边分别为a,b,c,a=4,c=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300025_ST/0.png)
,sinA=4sinB
(1)求b边的长;
(2)求角C的大小.
(3)如果
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300025_ST/1.png)
,求sinx.
考点分析:
相关试题推荐
已知向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300024_ST/0.png)
,设函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300024_ST/1.png)
.
(1)求f(x)的最小正周期与单调递减区间
(2)在△ABC中,a、b、c分别是角A、B、C的对边,若f(A)=4,b=1,△ABC的面积为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300024_ST/2.png)
,求a的值.
查看答案
已知函数f(x)=asinx+bcos(x-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300023_ST/0.png)
)的图象经过点(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300023_ST/1.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300023_ST/2.png)
),(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300023_ST/3.png)
,0).
(1)求实数a,b的值;
(2)求函数f(x)在[0,π]上的单调递增区间.
查看答案
在△ABC中,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300022_ST/0.png)
.
(1)求AB边的长度;
(2)求
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300022_ST/1.png)
的值.
查看答案
已知角α的顶点在原点,始边与x轴的正半轴重合,终边经过点
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300021_ST/0.png)
.
(1)求sin2α-tanα的值;
(2)若函数f(x)=cos(x-α)cosα-sin(x-α)sinα,求函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300021_ST/1.png)
在区间
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300021_ST/2.png)
上的取值范围.
查看答案
△ABC中内角A,B,C的对边分别为a,b,c,向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/0.png)
=(2sinB,-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/1.png)
),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/2.png)
=(cos2B,2cos
2![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/3.png)
-1)且
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/4.png)
∥
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124235343230013/SYS201310251242353432300020_ST/5.png)
.
(Ⅰ)求锐角B的大小;
(Ⅱ)如果b=2,求△ABC的面积S
△ABC的最大值.
查看答案