题目内容
(本小题满分12分)
已知函数
的图象与
轴交点的纵坐标为1,在相邻的两点
,
上
分别取得最大值和最小值.
(1) 求
的解析式;
(2) 若函数
的最大和最小值分别为6和2,求
的值.
已知函数
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227074931989.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707509310.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707524555.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227075401112.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707556495.png)
(1) 求
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707556495.png)
(2) 若函数
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707680769.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707712396.png)
(1)
;(2)
或
.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227077581306.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707790664.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707992655.png)
本试题主要是考查了三角函数关系式的化简以及三角函数性质的运用,求解其解析式,并能利用值域来解参数的值。
(1)依题意,得
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708024924.png)
最大值为2,最小值为-2,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708195418.png)
图象经过
,
,即
从而解得关系式。
(2)
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708570697.png)
分类讨论两种情况
或
解得,a,b的值。.
解:(1)依题意,得
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708024924.png)
最大值为2,最小值为-2,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708195418.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227082111214.png)
图象经过
,
,即![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708523607.png)
又
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227089601325.png)
(2)
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708570697.png)
或
解得,
或
.
(1)依题意,得
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708008790.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708024924.png)
最大值为2,最小值为-2,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708195418.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227082111214.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708367459.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708507580.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708523607.png)
(2)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227085381336.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708570697.png)
分类讨论两种情况
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708585918.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708601840.png)
解得,a,b的值。.
解:(1)依题意,得
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708008790.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708024924.png)
最大值为2,最小值为-2,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708195418.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227082111214.png)
图象经过
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708367459.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708507580.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708523607.png)
又
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708741600.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708772573.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227089601325.png)
(2)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232227085381336.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708570697.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708585918.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222708601840.png)
解得,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707790664.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823222707992655.png)
![](http://thumb.zyjl.cn/images/loading.gif)
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