题目
题型:不详难度:来源:
A.![]() | B.![]() | C.![]() | D.![]() |
答案
解析
设三边长分别是
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010750-48844.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010751-42636.png)
据余弦定理得:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010751-85144.png)
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010746-77351.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010746-27459.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010740-98475.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010740-39341.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010740-98475.png)
解:(i)由余弦定理可得,
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010740-26171.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-22593.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-71750.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-22593.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-13935.png)
故
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-80943.png)
(ii)设
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-80943.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010742-47032.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010742-44469.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010742-49929.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010742-90448.png)
故
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-80943.png)
综上可知,
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010741-80943.png)
请问:该学生的解答是否正确?若正确,请在下面横线中写出解题过程中主要用到的思想方法;若不正确,请在下面横线中写出你认为本题正确的结果. .
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010736-41854.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010736-39361.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010736-16289.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010736-39098.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010737-33215.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010728-68802.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010728-48068.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010728-54236.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010729-99885.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010729-53986.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010729-59073.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010725-77324.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010725-20383.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020010725-42876.png)
最新试题
- 1下列各说法中正确的是[ ]A.人推桌子未推动,是因为此时人的推力小于地面对桌子的摩擦力 B.维持物体的运动,必须
- 2已知函数的图像在点A(l,f(1))处的切线l与直线x十3y+2=0垂直,若数列的前n项和为,则S2013的值为 (
- 3若点为抛物线,则点到直线距离的最小值为 。
- 4读世界某区域图,完成下列各小题。(36分)(1)图中A河流的流向大致是 ,判断的理由是
- 5人在静脉注射时所用的生理盐水的浓度必须与血浆浓度基本相同,其中原因是[ ]A.维持内环境渗透压的稳定B.使体内增
- 6下列说法正确的是( )A.书放在水平桌面上,桌面受到了弹力,但书没有发生形变,所以书不受弹力B.书放在水平桌面上
- 7下列说法中正确的是( )A.1 mol Al3+含有的核外电子数为3×6.02×1023B.将58.5g NaC
- 8Once children reach the age of 18, they are encouraged to be
- 9按要求解决下列问题:(1)化简下列各式:21=______,82=______,183=______,505=_____
- 10某同学做“探究单摆的周期与摆长的的关系”的实验时,测得重力加速度的数值明显大于当地的重力加速度的实际值,造成这一情况的可
热门考点
- 1新疆正式归属我国中央政府管辖是在 [ ]A.秦朝B.西汉C.唐朝D.元朝
- 2— Bruce was killed in a traffic accident.— _____ I talked wi
- 3△ABC中AC>BC,边AB的垂直平分线与AC交于点D,已知AC=5,BC=4,则△BCD的周长是[ ]A.9B
- 4阅读下面的一篇文章,用一句话对此文内容作出归纳与评论。(不超20字)(5分)个别教育老师办公室里,老师在辅导学生。师:你
- 5三题中任选两题作答(1)(2011年江苏高考)已知矩阵A=1121,向量β=12,求向量α,使得A2α=β(2)(201
- 6二十一世纪,世界范围内各种思想文化相互融合、相互激荡。同时,西方一些势力扩大文化霸权,强势推销西方思想文化价值观。抵制西
- 7“某幼儿园给小朋友发苹果,若每个小朋友分3个则剩1个;若每个小朋友分4个则少2个,问苹果有多少个?” 若设共有x个苹果,
- 8若关于x的一元二次方程x2-6x+m=0有两个不相等的实数根,则m的取值范围是( )A.m<9B.m>9C.m>19D
- 9在旋转的过程中,要确定一个图形的旋转后的位置,除了知道原来图形的位置和旋转方向外,还需要知道______和______.
- 10The doctor suggested that he smoking. [ ]A.give upB