玉浊
幼苗
共回答了18个问题采纳率:83.3% 举报
(I)
![](https://img.yulucn.com/upload/9/dc/9dc37f8b55e86cf2f69667e57dd6a6e2_thumb.jpg)
是二次函数,且
![](https://img.yulucn.com/upload/c/ba/cba2a5de79e37a0782d9abf4b5aeb081_thumb.jpg)
的解集是
![](https://img.yulucn.com/upload/5/28/52879bfd52efae40a1b51bbb6b49bc98_thumb.jpg)
可设
![](https://img.yulucn.com/upload/a/ea/aeadcbe84370b74e2f25c38a0325348c_thumb.jpg)
--------------------------------2分
![](https://img.yulucn.com/upload/3/43/343f5fa3a001d0dee0e6a363e3d8b928_thumb.jpg)
在区间
![](https://img.yulucn.com/upload/e/b5/eb52514985b3da82460526bca89dab23_thumb.jpg)
上的最大值是
由已知,得
![](https://img.yulucn.com/upload/8/84/8848c24f36db76bc1ecea9f6027104e1_thumb.jpg)
-----
![](https://img.yulucn.com/upload/f/6f/f6ff5c37bef35fdf2f31aa9c643726fe_thumb.jpg)
------------------------4分
(II)方程
![](https://img.yulucn.com/upload/4/78/478bf2b04cf61b7ce1fd5df15fb461c9_thumb.jpg)
等价于方程
设
![](https://img.yulucn.com/upload/d/2d/d2d473c8faf5b9307bb36e159401ffaa_thumb.jpg)
则
当
![](https://img.yulucn.com/upload/b/44/b4473273ab726bebd088cdd4f5399b6c_thumb.jpg)
时,
![](https://img.yulucn.com/upload/6/41/641971d012840ea90cd3928c45b24ebd_thumb.jpg)
是减函数;
当
![](https://img.yulucn.com/upload/d/bc/dbcb353096db871b3bacea07b322ee65_thumb.jpg)
时,
![](https://img.yulucn.com/upload/6/db/6db1c90fafefd1b6962be8de3d6c6056_thumb.jpg)
是增函数.------------------------8分
![](https://img.yulucn.com/upload/5/28/52879bfd52efae40a1b51bbb6b49bc98_thumb.jpg)
方程
![](https://img.yulucn.com/upload/f/a4/fa46a0824c4a3dac088cb59fd7c1b7a4_thumb.jpg)
在区间
![](https://img.yulucn.com/upload/a/e8/ae8e88663904b7aba4f56e3a9662fecb_thumb.jpg)
内分别有惟一实数根,而在区间
![](https://img.yulucn.com/upload/9/e7/9e7d9ed5454ca82055b34bab45331a66_thumb.jpg)
内没有实数根.---------------------------------------------------------------10分
所以存
![](https://img.yulucn.com/upload/d/81/d817233c361380ce3cb21bbf55941a74_thumb.jpg)
在惟一的自然数
![](https://img.yulucn.com/upload/c/3f/c3f02554efd7e050889f9344a90c4581_thumb.jpg)
使得方程
![](https://img.yulucn.com/upload/4/78/478bf2b04cf61b7ce1fd5df15fb461c9_thumb.jpg)
在区间
![](https://img.yulucn.com/upload/c/6b/c6b5f4bdbca291347deae9bc20df5991_thumb.jpg)
内有且只有两个不同的实数根.-------------------------------------------------------12分
略
1年前
4