在△ABC中,a、b、c分别为内角A、B、C的对边,且2asinA=(2b+c)sinB+(2c+b)sinC
(Ⅰ)求A的大小;
(Ⅱ)若sinB+sinC=1,试判断△ABC的形状.
考点分析:
相关试题推荐
已知函数f(x)=cos2ωx+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394017_ST/0.png)
sinωxcosωx(ω>0)的最小正周期为π.
(1)若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394017_ST/1.png)
,求θ的值;
(2)求函数f(x)的单调区间及其图象的对称轴方程.
查看答案
已知向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394016_ST/0.png)
=(sin x,2cos x),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394016_ST/1.png)
=(2sin x,sin x),函数f(x)=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394016_ST/2.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394016_ST/3.png)
-1.
(1)求函数f(x)的最小正周期和最大值;
(2)在给出的直角坐标系中,画出f(x)在区间[0,π]上的图象.
查看答案
函数f(x)=2cos
2x+sin2x-1,给出下列四个命题:
①函数在区间
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/0.png)
上是减函数;
②直线
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/1.png)
是函数图象的一条对称轴;
③函数f(x)的图象可由函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/2.png)
的图象向左平移
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/3.png)
个单位长度而得到;
④若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/4.png)
,则f(x)的值域是
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394015_ST/5.png)
.
其中所有正确命题的序号是
.
查看答案
设
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394014_ST/0.png)
与
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394014_ST/1.png)
是两个不共线的向量,且向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394014_ST/2.png)
与
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394014_ST/3.png)
共线,则λ=
.
查看答案
已知函数f(x)=Asin(ωx+φ)(x∈R,A>0,ω>0,|φ|<
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429881839451/SYS201311031024298818394013_ST/0.png)
)的部分图象如图所示,则f(x)的解析式是
.
查看答案