解题方法
1 . 《九章算术》作为中国古代数学专著之一,在其“商功”篇内记载:“斜解立方,得两堑堵.斜解堑堵,其一为阳马,一为鳖臑”,鳖臑是我国古代数学对四个面均为直角三角形的四面体的统称.在长方体
中,已知
.
平面
;
(2)求
与平面
所成角的正弦值;
(3)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38c014c8923b1ce9dcb8b028dd8b9f0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61cdaadeae37736a1e6dd93fa1fe712f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4508dc6d9c91157836be679c0543cac.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc4fd5b13f66aaa25632811704596c44.png)
(3)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4508dc6d9c91157836be679c0543cac.png)
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解题方法
2 . 设
,已知函数
.
(Ⅰ)当
时,判断函数
的奇偶性;
(Ⅱ)若
恒成立,求
的取值范围;
(Ⅲ)设
,若关于
的方程
有实数解,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22dd8b3dc4c609bab82d356a5cc2208d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f64663000c9c761e53f018a9b54cd468.png)
(Ⅰ)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b4d795709b0abcf47bceec2250f2f9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17dee19e20ec748f8003a201f1d32539.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(Ⅲ)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dd0914dc4d4c7f75710ff460a286fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11f3dc4126f14210cd5d7ce715547053.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c925be255ca736a53b24d13ddede1a86.png)
您最近一年使用:0次