题目

（本小题满分14分） 设椭圆的左右焦点分别为、，是椭圆上的一点，，坐标原点到直线的距离为． （1）求椭圆的方程； （2）设是椭圆上的一点，过点的直线交轴于点，交轴于点，若，求直线的斜率． 答案：（本小题满分14分） 解：（1）由题设知 由于，则有，所以点的坐标为 故所在直线方程为 所以坐标原点到直线的距离为 又，所以  解得： 所求椭圆的方程为 （2）由题意可知直线的斜率存在，设直线斜率为 直线的方程为，则有 设，由于、、三点共线，且 根据题意得,解得或 又在椭圆上，故或 解按要求完成下列句子，每空一词1.The population of the city is about__three__millions．(对画线部分提问)______ ________ the population of the city?2.The emperor built the walls to__protect__their__countries．(对画线部分提问)______ _______the emperor _______ the walls?3.Qomolangma is the highest mountain in the world.(改为同义句)Qomolangma is _______ than _______ ___________ mountain in the world.4.This stone is two kilos.That stone is six kilos.(合并成一个句子)That stone is four _______ __________ than this one.5.Tom's room is smaller than Andy's room.(改为同义句)Tom's room is not ________ ________ ________ Andy's room.6.You'll be late for class unless you take a taxi.(改为同义句)_______ you ______take a taxi，you'll be late for class.7.He went to a doctor because he had a bad cold．(对画线部分提问)_______ _______he_______to a doctor?8.We can see some pictures on the wall.(改为否定句)We______see______pictures on the wall.9.The beautiful girl will marry a writer next month.(改为同义句)The beautiful girl will_______ ______ ______a writer next month.10.She was so weak that she couldn't keep running.(改为同义句)She was______weak______keep running. 1. What is 2. Why did build 3. higher any other 4. kilos heavier 5. as/so big as 6. If don’t 7. Why did go 8. can’t any 9. get married to 10. too to 【解析】 1.The populat...