名校
解题方法
1 . 设连续函数
的定义域为
,如果对于
内任意两数
,都有
,则称
为
上的凹函数;若
,则称
为凸函数.若
是区间
上的凹函数,则对任意的
,有琴生不等式
恒成立(当且仅当
时等号成立).
(1)证明:
在
上为凹函数;
(2)设
,且
,求
的最小值;
(3)设
为大于或等于1的实数,证明:
.(提示:可设
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f030c36bb8786df88d401792062a4100.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f030c36bb8786df88d401792062a4100.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a7a1783349936cc7254a4a8694c6812.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f030c36bb8786df88d401792062a4100.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1bedaf3854b48806b82b3b804451cf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f030c36bb8786df88d401792062a4100.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0fec4d10407498ec4692b33ebe1bb7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a1784a3a9dd90c51dab965445d65f08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2697ef67790838c84cc238a0334c5d47.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/008ab9b6200370bd8d534a6317cb88e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7160d93f92089ef36f3dab809d3114b8.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6da13af19b32430759c9c1d1aea894e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b16ad49f62d7362441e3b92efe7f87d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b47ade684a2e49ef6139afe6ab59a29.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1d4c274b53adfbffc4b19e7adbc39d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6694499b581256296277c515f6dcdc8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10cda4049695561dab3e0803c3a287fe.png)
您最近一年使用:0次
2 . 借助信息技术计算
的值,我们发现当
时
的底数越来越小,而指数越来越大,随着
越来越大,
会无限趋近于
(
是自然对数的底数).根据以上知识判断,当
越来越大时,
会趋近于__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d285a6a3ca6b2b04d5397183436b5b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62dbd49de67f043222d84023bbc870fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b3f779c42398b1158faa9f9124ed13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b3f779c42398b1158faa9f9124ed13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/041a7c8fc017f596542c5e6ec7d1c40b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11204e2fb6e560bf7a4ca26eaebfc526.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eda3a356637a488a68626a6427b34a43.png)
您最近一年使用:0次