shuapiao023
春芽
共回答了20个问题采纳率:90% 举报
(Ⅰ)函数解析式为
![](https://img.yulucn.com/upload/c/d8/cd84f884b435ed898331c82b8f916aed_thumb.jpg)
.(Ⅱ)当
![](https://img.yulucn.com/upload/e/63/e636ed36effa723b53f765215695bcd1_thumb.jpg)
时,函数
![](https://img.yulucn.com/upload/8/4b/84be1cdf19acee6d58363a67e9ad3d5b_thumb.jpg)
1 取得最小值1.
本试题主要是考查了哈数解析式的求解以及函数的最值问题的研究
(1)因为点
![](https://img.yulucn.com/upload/2/f0/2f015f6a3f42f72de4a777d13edb23b7_thumb.jpg)
关于直线
![](https://img.yulucn.com/upload/e/63/e636ed36effa723b53f765215695bcd1_thumb.jpg)
的对称点Q的坐标为
![](https://img.yulucn.com/upload/0/d7/0d7695320d8729c4c71d6401aaa3e968_thumb.jpg)
.再由由
![](https://img.yulucn.com/upload/d/c9/dc9f6f33902873bb8131e3e734c68038_thumb.jpg)
得
![](https://img.yulucn.com/upload/7/74/774b8ece43f141e36c825b5ad7efbf5f_thumb.jpg)
得到参数m,a的值,求得解析式。
(2)因为
![](https://img.yulucn.com/upload/8/4b/84be1cdf19acee6d58363a67e9ad3d5b_thumb.jpg)
0
![](https://img.yulucn.com/upload/5/b4/5b47932cdb9535bc2b6ed226c7dfa0eb_thumb.jpg)
(
![](https://img.yulucn.com/upload/f/9e/f9ecc28169b275dc5668dd0b9c3a3efa_thumb.jpg)
),然后利用均值不等式得到最值。
(Ⅰ)点
![](https://img.yulucn.com/upload/2/f0/2f015f6a3f42f72de4a777d13edb23b7_thumb.jpg)
关于直线
![](https://img.yulucn.com/upload/e/63/e636ed36effa723b53f765215695bcd1_thumb.jpg)
的对称点Q的坐标为
![](https://img.yulucn.com/upload/0/d7/0d7695320d8729c4c71d6401aaa3e968_thumb.jpg)
.·········· 2分
由
![](https://img.yulucn.com/upload/d/c9/dc9f6f33902873bb8131e3e734c68038_thumb.jpg)
得
![](https://img.yulucn.com/upload/7/74/774b8ece43f141e36c825b5ad7efbf5f_thumb.jpg)
······················· 4分
解得
![](https://img.yulucn.com/upload/9/bf/9bf1fd6f10d53d7211d9967cc2b05e60_thumb.jpg)
,
![](https://img.yulucn.com/upload/7/bf/7bf7b042de96929bab6f17d48cbca9b8_thumb.jpg)
,故函数解析式为
![](https://img.yulucn.com/upload/c/d8/cd84f884b435ed898331c82b8f916aed_thumb.jpg)
.············ 6分
(Ⅱ)
![](https://img.yulucn.com/upload/8/4b/84be1cdf19acee6d58363a67e9ad3d5b_thumb.jpg)
0
![](https://img.yulucn.com/upload/5/b4/5b47932cdb9535bc2b6ed226c7dfa0eb_thumb.jpg)
(
![](https://img.yulucn.com/upload/f/9e/f9ecc28169b275dc5668dd0b9c3a3efa_thumb.jpg)
),
····································· 8分
∵
![](https://img.yulucn.com/upload/b/f1/bf1e424c7e2beb7e3960f444b1aa82a2_thumb.jpg)
,
当且仅当
![](https://img.yulucn.com/upload/a/b6/ab6bc3b6bdab457925f9297e65e5738d_thumb.jpg)
即
![](https://img.yulucn.com/upload/e/63/e636ed36effa723b53f765215695bcd1_thumb.jpg)
时,“=”成立, ················ 10分
而函数
![](https://img.yulucn.com/upload/f/36/f36d163d86c6aaa6dcb6a3545e453ad0_thumb.jpg)
在
![](https://img.yulucn.com/upload/8/0a/80a0806339a0db5f036f2a5d87177af9_thumb.jpg)
上单调递增,则
![](https://img.yulucn.com/upload/8/4b/84baa42b25b8c54d52bbd48a0811bebe_thumb.jpg)
,
故当
![](https://img.yulucn.com/upload/e/63/e636ed36effa723b53f765215695bcd1_thumb.jpg)
时,函数
![](https://img.yulucn.com/upload/8/4b/84be1cdf19acee6d58363a67e9ad3d5b_thumb.jpg)
1 取得最小值1.··················· 12分
1年前
2