當X=3時，Y最小值=-1，且圖像過（0,7），求關於X的二次函數解析式

由此可以設二次函數的解析式為：
y=a*（x-3）^2-1，其中a大於0
又有：
7=a*（0-3）^2-1，解得：
a=8/9.則有：
此二次函數的解析式為：
y=8*（x-3）^2/9-1

已知二次函數的圖像經過點（0，-2），且當x=1時函數有最小值-3.（1）求這個二次函數的解析式；（2）如果點（-2，y1），（1，y2）和（3，y3）都在該函數圖像上，試比較y1，y2，y3的大小.

（1）由題意知：抛物線的頂點座標為（1，-3）設二次函數的解析式為y=a（x-1）2-3，由於抛物線過點（0，-2），則有：a（0-1）2-3=-2，解得a=1；囙此抛物線的解析式為：y=（x-1）2-3.（2）∵a=1＞0，∴故抛物線的開口向上；∵抛物線的對稱軸為x=1，∴（1，y2）為拋物線的頂點座標，∴y2最小.由於（-2，y1）和（4，y1）關於對稱軸對稱，可以通過比較（4，y1）和（3，y3）來比較y1，y3的大小，由於在y軸的右側是增函數，所以y1＞y3.於是y2＜y3＜y1.

已知二次函數的影像過點（2,7），且當x=-2時有最小值-1，則這個二次函數的解析式是

二次函數的影像過點（2,7），且當x=-2時有最小值-1，
設這個二次函數是
y=a（x+2）²；-1，且a（2+2）²；-1=7 16a=8 a=1/2
∴這個二次函數的解析式是
y=1/2（x+2）²；-1
即y=1/2x²；+2x+1

蘇教版九年級上册《數學創新課時練》答案

練習題（1）
在同圓或等圓中，相等的圓心角所對的弧相等，所對的弦也相等.
在同圓或等圓中，如果兩條弧相等，那麼他們所對的圓心角_____.所對的弦_；
在同圓或等圓中，如果兩條弦相等，那麼他們所對的圓心角_.所對的弧_；

全部是相等的，不信你可以畫圖看.

誰能給一些定語從句的練習？我現在上國中
如果好的話我有重賞哦！
還有最好多一些是用“whose，whom”的題目，這是我的最最最弱項了！我上的是國中只要“that，who，which，whom，whose”這些答案的題目.

1、The people（）you were talking to are Russians.
A that B who C which D whom
答案是A.
that用作介詞to的賓語，常省略.介詞to
緊隨動詞之後，不能放在that前面.
2、The man（）I saw is called Bob.
A whom B whose C who D which
答案是C.
who用作賓語，代替whom，常省略，此處也可用that .
3、I'd like a room（）window looks out over the sea.
A that B which C whose D whom
答案是C.
whose也可指物，在從句中用作定語
4、This is the man（）I referred to.
A who B whose C whom D which
答案是C.
whom用作介詞to的賓語，介詞緊跟動詞之後.

國中定語從句練習

1.The place _______interested me most was the Children's Palace.
A. Which B. where C. what D. in which
3.This is the hotel _______last month.
A. which they stayed B. at that they stayed
C. where they stayed at D. where they stayed
4.Do you know the year ______the Chinese Communist Party was founded？
A. which B. that C. when D. on which
5.That is the day ______I'll never forget.
A. which B. on which C. in which D. when
6.The factory ______we'll visit next week is not far from here.
A. where B. to which C. which D. in which
8.This is one of the best films _______.
A. that have been shown this year B. that have shown
C. that has been shown this year D. that you talked
9.Can you lend me the book ______the other day？
A. about which you talked B. which you talked
C. about that you talked D. that you talked
10.The pen ______he is writing is mine.
A. with which B. in which C. on which D. by which
11.They arrived at a farmhouse，in front of ______sat a small boy.
A. whom B. who C. which D. that
12.The engineer ______my father works is about 50 years old.
A. to whom B. on whom C. with which D. with whom
13.It there anyone in your class ______family is in the country？
A. who B. who's C. which D. whose
14.I'm interested in ______you have said.
A. all that B. all what C. that D. which
15.I want to use the same dictionary ______was used yesterday.
A. which B. who C. what D. as
16.He isn't such a man ______he used to be.
A. who B. whom C. that D. as
17.He is good at English，______we all know.
A. that B. as C. whom D. what
18.Li Ming，______to the concert enjoyed it very much.
A. I went with B. with whom I went C. with who I went D.I went with him
19.I don't like ______as you read.
A. the novels B. the such novels C. such novels D. same novels
20.He talked a lot about things and persons ________they remembered in the school.
A. which B. that C. whom D. what
21.The letter is from my sister，______is working in Beijing.
A. which B. that C. whom D. who
22.In our factory there are 2000 workers，two thirds of ____are women.
A. them B. which C. whom D. who
23.You're the only person ______I've ever met ______could do it.
A. who；/ B./；whom C. whom；/ D./；who
24.I lost a book，______I can't remember now.
A. whose title B. its title C. the title of it D. the title of that
25.Last summer we visited the West Lake，______Hangzhou is famous in the world.
A. for which B. for that C. in which D. what
26.I have bought such a watch _______was advertised on TV.
A. that B. which C. as D. it
27.I can never forget the day _______we worked together and the day ______we spent together.
A. when；which B. which；when C. what；that D. on which；when
28.The way ______he looks at problems is wrong.
A. which B. whose C. what D./
29.This is the reason ______he didn't come to the meeting.
A. in which B. with which C. that D. for which
30.This machine，______for many years，is still working perfectly.
A. after which I have looked B. which I have looked after
C. that I have looked after D. I have looked after
31.The reason ______he didn't come was ______he was ill.
A. why；that B.that；why C. for that；that D.for which；what
32.He is working hard，______will make him pass the final exam.
A.that B.which C.for which D.who
33.That is not the way ______I do it.
A./ B.which C.for which D.with which
34.I have two grammars，______are of great use.
A. all of which B. either of which C. both of that D. both of which
35.I want to use the same tools _______used in your factory a few days ago.
A. as was B. which was C. as were D. which
36.My neigh bours used to give me a hand in time of trouble，_______was very kind of them.
A. who B. which C. that D. it
37.This is the magazine _______I copied the paragraph.
A. that B. which C. from that D. from which
38.He is not such a man _______would leave his work half done.
A. that B. which C. who D. as
39. You can depend on whatever promise _______he makes.
A. / B. why C. when D. whose
40. Smoking，_______is a bad habit，is，however，popular.
A. that B. which C. it D. though
41. --- Did you ask the guard _______happened？
--- Yes，he told me all _______he knew.
A. what；that B. what；what C. which；which D. that；that
42. I shall never forget those years _______I lived on the farm with
the farmers，_______has a great effect on my life.
A. when；who B. that；which C. which；that D. when；which
43. The number of the people who _______cars _______increasing.
A. owns；are B. owns；is C. own；is D. own；are
44. During the days ________，he worked as a servant at the Browns.
A. followed B. following C. to follow D. that followed
45. Is oxygen the only gas _______helps fire burn？
A. that B. / C. which D. it
46. The clever boy made a hole in the wall，_______he could see _____was going on inside house.
A. which；what B. through which；what C. through that；what D. what；that
47. Is _______some German friends visited last week？
A. this school B. this the school C. this school one D. this school where
48. John got beaten in the game，_______had been expected.
A. as B. that C. what D. who
49. I have bought two ballpens，_______writes well.
A. none of them B. neither of them C. neither of which D. none of which
50. All that can be eaten _______eaten up.
A. are being B. has been C. had been D. have been
參考答案及解析
1. A. which用作關係代詞，在定語從句中作主語.
2.C.“和誰講話”要說speak to sb.本題全句應為Do you know the man whom I spoke to..whom是關係代詞，作介詞to的賓語，可以省略.
3. D. where是關係副詞，表示地點，在定語從句中作地點狀語.
4. C. when是關係副詞，表示時間，在定語從句中作時間狀語.
5.A. which是關係代詞，在從句中作forget的賓語.其他幾個答案都不能作賓語.
6.C.解析同第5題.
7. A.解析見第3題.
8. A.本句話的先行詞應該是films，囙此，關係代詞that是負數概念，其謂語動詞應用複述的被動語態have been shown.如果句中的one前面使用了定冠詞the，則the one應該視為先行詞.
9. A.“談到某事物”應說talk about sth..about是介詞，其後要用which作賓語，不能用that.
10. A. with which是“介詞+關係代詞”結構，常用來引導定語從句.with有“用”的意思，介詞之後只能用which，不能用that. with which在定語從句中作狀語，即he is writing with a pen.
11. C. in front of which即in front of a farmhouse. In front of which在從句中作狀語.
12. D. with whom引導定語從句.with whom放在從句中即為：my father works with the engineer.
13. D. whose引導定語從句，在從句中作主語family的定語.
14. A. that引導定語從句，因為先行詞是all，所以只能選用that引導.
15. D. the same……..as是固定用法，as引導定語從句時，可以作主語，賓語或表語.在本句話中，as作從句的主語.
16. D. such………as是固定用法，as引導定語從句時，可以作主語，賓語或表語.在本題中，as作表語.
17. B. as作關係代詞可以單獨用來引導非限制性定語從句.這時as所指代的不是主句中某個名詞，而往往指代整個主句的含義.as在從句中可以作主語、賓語.從句可放在主句後，也可置於主句前.在本句中，as作賓語.
18. B. Li Ming enjoyed it very much是主句，with whom I went to the concert是定語從句.with wh

當X=3時，Y最小值=-1，且圖像過（0,7），求關於X的二次函數解析式