题目内容
已知![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450850.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450966.png)
,
且
的最小正周期为
.
(1)求
的单调递减区间. (2)求
在区间
上的取值范围.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450850.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450966.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481623.png)
且
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538512309.png)
(1)求
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538575615.png)
(1)
的单调递减区间是
(2)
在区间
上的取值范围
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538637974.png)
(2)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538575615.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538700525.png)
本试题主要是考查了三角函数的图像和性质的运用。
(1)因为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450850.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450966.png)
,
且
的最小正周期为
,那么利用数量积
得到![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
,从而得到w的值
(2)因为
,结合函数图像求解值域即为所求解的范围。
(1)因为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450850.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538450966.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481623.png)
且
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538512309.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232305388241174.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538481447.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823230538871952.png)
(2)因为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232305388871168.png)
![](http://thumb.zyjl.cn/images/loading.gif)
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