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共回答了15个问题采纳率:100% 举报
解题思路:本题主要考查极坐标方程与直角坐标方程的互化,直线的参数方程,韦达定理等基础知识,考查学生的转化能力和计算能力 第一问,利用极坐标与直角坐标的互化公式
![](https://img.yulucn.com/upload/e/b6/eb61b7968e62804d50668669963c06d2_thumb.jpg)
,
![](https://img.yulucn.com/upload/6/9a/69abf680618e2bb4221848143a185999_thumb.jpg)
进行互化,并写出图形形状;第二问,由直线
![](https://img.yulucn.com/upload/5/7f/57f1825d008d1bc6e8818dfe902524f8_thumb.jpg)
的参数方程得出直线过
![](https://img.yulucn.com/upload/2/23/223fba1eb99a4a143231690c18fa1652_thumb.jpg)
,若还过
![](https://img.yulucn.com/upload/d/f3/df35a836874054145fedaaabb7edfebf_thumb.jpg)
,则
![](https://img.yulucn.com/upload/0/b7/0b75aaad0db80c60b6b1002436ab7d82_thumb.jpg)
,则直线
![](https://img.yulucn.com/upload/5/7f/57f1825d008d1bc6e8818dfe902524f8_thumb.jpg)
的方程可进行转化,由于直线与曲线C相交,所以两方程联立,得到关于t的方程,设出A,B点对应的参数
![](https://img.yulucn.com/upload/0/d9/0d9bbefb1401fb500f07f0b3a8061bd0_thumb.jpg)
,所以
![](https://img.yulucn.com/upload/7/8b/78b975663a765aabbd3d20e09058ad1a_thumb.jpg)
,利用两根之和,两根之积进行转化求解
试题解析:(1)曲线C的直角坐标方程为
![](https://img.yulucn.com/upload/3/03/303c0b90c62197acefab2cf65d0e94f7_thumb.jpg)
,故曲线C是顶点为O(0,0),焦点为F(1,0)的抛物线; 5分
(2)直线
![](https://img.yulucn.com/upload/5/7f/57f1825d008d1bc6e8818dfe902524f8_thumb.jpg)
的参数方程为
![](https://img.yulucn.com/upload/2/3e/23ed291de78546c31328741a700fbe33_thumb.jpg)
( t为参数,0≤
![](https://img.yulucn.com/upload/5/1a/51a3824aadec366ede20fcda2b80af17_thumb.jpg)
<
![](https://img.yulucn.com/upload/2/e8/2e8898e245e2ae34442ad9b789470808_thumb.jpg)
) 故l经过点(0,1);若直线
![](https://img.yulucn.com/upload/5/7f/57f1825d008d1bc6e8818dfe902524f8_thumb.jpg)
经过点(1,0),则
![](https://img.yulucn.com/upload/5/5b/55b63e76d1f2169fe3379e28f9594730_thumb.jpg)
直线
![](https://img.yulucn.com/upload/5/7f/57f1825d008d1bc6e8818dfe902524f8_thumb.jpg)
的参数方程为
![](https://img.yulucn.com/upload/b/4d/b4d7d440dd4c354f5bddbbeab7d31648_thumb.jpg)
(t为参数)
代入
![](https://img.yulucn.com/upload/3/03/303c0b90c62197acefab2cf65d0e94f7_thumb.jpg)
,得
设A、B对应的参数分别为
![](https://img.yulucn.com/upload/5/4b/54b8ef771128bbf510bcde23c41376b7_thumb.jpg)
,则
![](https://img.yulucn.com/upload/3/91/39139504c4d8e710d80a717106ac686b_thumb.jpg)
="8" 10分
(1)
,曲线C是顶点为O(0,0),焦点为F(1,0)的抛物线;(2)8
1年前
3