解题方法
1 . 已知
为实数,函数
,
.
(1)当
时,求函数
的单调递增区间;
(2)若对任意
,
恒成立,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b17a4b14ea764bdbe93aea9359bb7a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb63478132d4c1fef3c17e591919da83.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(2)若对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047056c99b39c70fa40d3c8178e5b631.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a71baf6217604517fd98fa97d0f55b43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
您最近一年使用:0次
2 . 某公司想了解对某产品投入的宣传费用与该产品的营业额的影响.右图是以往公司对该产品的宣传费用
(单位:万元)和产品营业额
(单位:万元)的统计折线图.
![](https://img.xkw.com/dksih/QBM/2018/7/11/1986197480456192/2020301789233152/STEM/be16c243c00548228e2c8a059c43b9c8.png?resizew=246)
(Ⅰ)根据折线图可以判断,可用线性回归模型拟合宣传费用
与产品营业额
的关系,请用相关系数加以说明;
(Ⅱ)建立产品营业额
关于宣传费用
的回归方程;
(Ⅲ)若某段时间内产品利润
与宣传费
和营业额
的关系为
应投入宣传费多少万元才能使利润最大,并求最大利润. (计算结果保留两位小数)
参考数据:
,
,
,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9d9f5886155f5d9f10a110103a9f7f.png)
参考公式:相关系数
,回归方程
中斜率和截距的最小二乘法估计公式分别为
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://img.xkw.com/dksih/QBM/2018/7/11/1986197480456192/2020301789233152/STEM/be16c243c00548228e2c8a059c43b9c8.png?resizew=246)
(Ⅰ)根据折线图可以判断,可用线性回归模型拟合宣传费用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
(Ⅱ)建立产品营业额
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(Ⅲ)若某段时间内产品利润
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba03c5cfa528b78f2574a7121163314b.png)
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f4b91c58e313996d017d296bc563514.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a3d851f425de5fa60525705c8d63b9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfb1a6871cd0d84271b9452a4d5f3b77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1705bf427c5b90d3092ceff4d1865a4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9d9f5886155f5d9f10a110103a9f7f.png)
参考公式:相关系数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9da0639581f543d25577b4090419af9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02070b036d0efab71df26b085c24af5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f87f8b6571be2d72b37efdd7453547b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/154d8462e6416b61dc7b0f5a6e62c2df.png)
您最近一年使用:0次
3 . 已知
,设函数
.
(1)若
时,求
函数的单调区间;
(2)若
,对于任意的
,不等式
恒成立,求实数
的最大值及此时
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da989240786ef7c3e2d903f30caf59e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97d1f5b4361a7e8e70601e77b4c6afc7.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65397f11ea8af736f38debadf420c4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2970490a24c4f32959ec00365f221766.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a183383c12ed030ced3ff37a6ec6e6fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/097a5dfcc1c0cddbfde811b2ccfd4a94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
您最近一年使用:0次