Câu 1 : Cho hình lập phương ABCDEFGH ,góc giữa hai véc tơ \(\overrightarrow{AC},\overrightarrow{BG}\) là :

A. 45⁰

B. 30⁰

C. 60⁰

D. 120⁰

Câu 2 : Cho tứ diện ABCD có AB = CD = a , IJ = \(\frac{a\sqrt{3}}{2}\) ( I , J lần lượt là trung điểm của BC và AD ) . Số đo giữa hai đường thẳng AB và CD là :

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 3 : Cho hình chóp S.ABCD có SA vuông góc với (ABCD) , đáy ABCD là hình chữ nhật . Biết SA = a\(\sqrt{3}\) , AB = a , AD = \(a\sqrt{3}\) . Số đo giữa cạnh bên SB và cạnh AB là :

A. 60⁰

B. 45⁰

C. 90⁰

D. 30⁰

Câu 4 : Cho tứ diện ABCD đều cạnh bằng a . Gọi M là trung điểm CD , \(\alpha\) là góc giữa AC và BM . Chọn khẳng định đúng ?

A. \(cos\alpha=\frac{\sqrt{3}}{4}\)

B. \(cos\alpha=\frac{1}{\sqrt{3}}\)

C. \(cos\alpha=\frac{\sqrt{3}}{6}\)

D. \(\alpha=60^0\)

Câu 5: Cho tứ diện ABCD với \(AB\perp AC\) , \(AB\perp BD\) . Gọi P , Q lần lượt là trung điểm của AB và CD . Góc giữa PQ và AB là :

A. 90⁰

B. 60⁰

C. 30⁰

D. 45⁰

Câu 6 : Cho hình thoi ABCD có tâm O , AC = 2a . Lấy điểm S không thuộc (ABCD) sao cho \(SO\perp\left(ABCD\right)\) . Biết tan \(\widehat{SOB}\) = \(\frac{1}{2}\) . Tính số đo của góc giữa SC và (ABCD)

A. 75⁰

B. 45⁰

C. 30⁰

D. 60⁰

Câu 7 : Cho hình chóp S.ABC có \(SA\perp\left(ABC\right)\) và tam giác ABC không vuông . Gọi H , K lần lượt là trực tâm \(\Delta ABC\) và \(\Delta SBC\) . Số đo góc tạo bởi SC và mp (BHK) là :

A. 45⁰

B. 120⁰

C. 90⁰

D. 65⁰

Câu 8 : Cho hình chóp S.ABC có đáy ABC là tam giác đều cạnh a , \(SA\perp\left(ABC\right)\) , \(SA=a\frac{\sqrt{3}}{2}\) . Gọi (P) là mặt phẳng đi qua A và vuông góc với trung tuyến SM của tam giác SBC . Thiết diện của (P) và hình chóp S.ABC có diện tích bằng ?

A. \(\frac{a^2\sqrt{6}}{8}\)

B. \(\frac{a^2}{6}\)

C. \(a^2\)

D. \(\frac{a^2\sqrt{16}}{16}\)

Câu 9 : Cho hình chóp S.ABC có đáy ABC là tam giác đều cạnh a . Hình chiếu vuông góc của S lên (ABC) trùng với trung điểm H của cạnh BC . Biết tam giác SBC là tam giác đều . Tính số đo của góc giữa SA và (ABC)

A. 60⁰

B. 75⁰

C. 45⁰

D. 30⁰

HELP ME !!!! giải chi tiết giùm mình với ạ

I. PHONETICS (1 m )

Choose one word whose underlined part is pronounced differently

1. A. floors B. bags C. swims D. lips ( gạch chân đuôi s )

2. A. looked B. crossed C. loved D. stopped ( gạch chân đuôi ed )

Choose one word whose stress pattern is different

1. A. variety B. ability C. solidarity D. facilities

2. A. become B. nation C. gather D. cycling

II. VOCABULARY AND GRAMMAR

Choose the one word or phrase ( A,B,C or D ) that best completes the sentences or substitutes for the underlined words or phrases (2ms)

1. I specially indulge ..................... some hobbies

A. at B. of C. from D. in

2. The most important thing is to keep yourself occupied

A. free B. busy C. relaxed D. comfortable

3. The singer was .............. on the piano by her sister

A. played B. perfomed C. accompanied D. helped

4. This is the book ..................... you lent me last week

A. who B. when C. where D. X

5. The film was about John .............................. was a doctor

A. whom B. that C. whose D. who

6. ..................................... England won the World Cup

A. It was in 1966 that B. It was on 1966 that

C. It was in 1966 when D. It was 1966 in that

7. The Vietnamese participants always take part ................... sports events with great enthusiasm

A. at B. on C. to D. in

8. The death of his son was an experience from .................... he never fully recovered

A. which B. when C. that D. why

Complete the sentences with one appropriate word (1 m )

1. The Asian Games take ......................... every four years

2. There were elven countries .................................. part in the 1^st Asian Games

3. Lewis established a new world .......................... with a time of 9.86 seconds

4. Swimming and water skiing are both ........................... sports

Give the correct form of the given at the end of the sentence (1 m )

1. My brother is an accomplished ......................... ( guitar )

2. The athletes ............................... in 38 different sports and won 427 gold medals at the 14^th Asian Games ( competition )

3. Jack has a large .................... of foreign coins ( collect )

4. Don is ....................... in playing football ( interest )

II. READING

Read the passage and do the tasks :

The Asian Games owes its origins to small Asian multi-sport competitions . The Far Eastern Championship Games were created to show unity and cooperation among three nations : Japan , the Philippines and China . The first games were held in Manila , the Philippines in 1931 . Other Asian nations participated after it was organized . After World War II , a number of Asian countries became independent . Many of the new independent Asian countries wanted to use a new type of competition where Asian dominance should not be shown by violence and should be strengthened by mutual understanding . In August 1948 , during the 14th Olympic Games in London , Indian representative Guru Dutt Sondhi proposed to sports leaders of the Asian teams the idea of having discussions about holding the Asian Games . They agreed to form the Asian Athletic Federation . A preparatory committee was set up to draft the charter for the Asian amateur athletic federation . In February , 1949 , the Asian athletic federation was formed and used the name Asian Games Federation . It was decided to hold the first Asian Games in 1951 in New Delhi the capital of India . They added that the Asian Games would be regularly held once every four years .

Task 1: Decide whether the statements are True (T) or False (F) : (0,5 m )

1. ........................... The text is about the origin of the Asian Games

2. ....................... The Far Eastern Championship Games had the participation of only four nations : Japan , the Philippines , China and India

Task 2 : Answer the questions : ( 1 m )

1. When / 14^th Olympic Games / take place ?

.........................................................................................................................................................

2. first Asian Games / hold / 1951 / India ?

..........................................................................................................................................................

Read the passage and choose the best answer for each question

The 15^th Asian Games (1).................... from December 1 through December 15 , 2006 , in Doha , Capital of Qatar . More than 10,000 (2)..................... , who (3) ...................... 45 countries and regions , (4) ............... in 39 sports and 424 events of the Games , the most important event in Asian . Some new events such as chess and triathlon were also included in the Games

1. A. set up B. took part C. brought out D. took place

2. A. athletes B. listeners C. speakers D. referees

3. A. symbolized B. represented C. expressed D. typified

4. A. set up B. took part C. brought out D. took place

IV. WRITING ( 2 ms )

1. The neighbor told them about it ( Cleft sentence , gạch chân the neighbor )

..........................................................................................................................................

2. You sent me a present . Thank you very much for it ( Relative clause )

.............................................................................................................................

3. We are coming to stay with Jane this weekend ( Cleft sentence , gạch chân Jane )

....................................................................................................................................................

4. This is the sweater . I bought it on Saturday ( Omission of relative pronoun )

.........................................................................................................................................

Make meaningful sentences with the cues given ( 0.5 )

My stamp collection / began / I / was / 11-year-old boy .

..........................................................................................................................................

giải giúp mình cái đề này với ạ

Câu 1 :

a) Cho hàm số y = f (x) = \(\frac{mx^2}{3}-\frac{mx^2}{2}+\left(3-m\right)x-2\) . Xác định m để f ^' ( x) > 0 , \(\forall\) x \(\in\) R

b) Cho hàm số y = x³ - 5x² + 2 có đồ thị (C) . Viết phương trình tiếp tuyến của đồ thị (C) biết tiếp tuyến vuông góc với đường thẳng (d) : x + 8y - 2019 = 0

Câu 2 : Cho hình chóp S.ABCD có đáy ABCD là hình vuông cạnh a , SA vuông góc với mặt phẳng (ABCD) và SA = 2a

a. Chứng minh BD \(\perp\) (SAC)

b. Tính góc giữa SB và (SAD)

c. Tính cô sin của góc tạo bởi hai mặt phẳng (SAC) và (SCD)

HELP ME !!!!!!!!!!

Câu 1: Tìm các giới hạn sau :

a) lim \(\frac{n^2+2n+1}{2n^2-1}\)

b) lim \(\frac{2\sqrt{x+1}-x^2+2x+2}{x}\) ( x \(\rightarrow\) 0 )

Câu 2: Cho hàm số y = f (x ) = \(\frac{x+1}{2x-1}\) có đồ thị (C)

a. Viết phương trình tiếp tuyến của đồ thị (C) tại điểm có hoành độ bằng -1

b. Viết phương trình tiếp tuyến của đồ thị (C) tại điểm có tung độ bằng 1

c. Viết phương trình tiếp tuyến của đồ thị (C) tại giao điểm của đồ thị (C) với trục tung

d. Viết phương trình tiếp tuyến của đồ thị (C) biết tiếp tuyến song song với đường thẳng d có phương trình 6x + 2y - 1 = 0

Câu 3: Tìm đạo hàm của các hàm số

a) y = sin² 2x ;

b) y = x⁴ - 2x² + 1 ;

c) y = \(\frac{3x-1}{x+2}\) ;

d) y = \(\left(x^2+x+1\right)^{10}\)

e) y = \(\sqrt{2x^2-x+3}\)

HELP ME !!!!!

Câu 1: Cho hình chóp S.ABCD có \(SA\perp\left(ABCD\right)\) , \(SA=\sqrt{3}AB\) và ABCD là hình vuông . Tính số đo góc giữa hai đường thẳng SB và CD

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 2: Cho hình chóp S.ABCD có đáy ABCD là hình vuông và \(SA\perp\left(ABCD\right)\) . Biết AB = a , \(SA=a\sqrt{6}\) , tính số đo giữa đường thẳng SC và mặt phẳng ( ABCD )

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 3 : Cho hình chóp S.ABCD có đáy ABCD là hình chữ nhật và \(SA\perp\left(ABCD\right)\) . Biết \(AD=a\sqrt{2}\) , CD = a , \(SD=a\sqrt{5}\) , tính số đo giữa đường thẳng SC và mặt phẳng (ABCD)

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 4: Cho hình chóp S.ABCD có đáy ABCD là hình vuông , \(SA\perp\left(ABCD\right)\) , SA = AB và M là trung điểm SB . Tính số đo giữa hai đường thẳng AM và BD

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 5 : Cho hình chóp S.ABCD có đáy ABCD là hình thang cân , \(SA\perp\left(ABCD\right)\) , AD // BC , SA = AB = BC = CD = 1/2 AD . Tính số đo góc giữa đường thẳng SC và mp (ABCD)

A. 30⁰

B. 45⁰

C. 60⁰

D. 90⁰

Câu 6 : Cho hình chóp S.ABC , \(SA\perp\left(ABC\right)\) , \(\Delta\)ABC vuông tại B , SA = AB = a , BC = a\(\sqrt{3}\) . Mặt phẳng \(\left(\alpha\right)\) qua A , vuông góc với SB . Tính diện tích thiết diện của hình chóp khi cắt bởi mp \(\left(\alpha\right)\)

A. \(\frac{a^2\sqrt{10}}{5}\)

B. \(\frac{a^2\sqrt{15}}{10}\)

C. \(\frac{a^2\sqrt{6}}{8}\)

D. \(\frac{a^2\sqrt{15}}{20}\)

help me !! giải chi tiết từng câu giúp mình với ạ

Choose the word or phrase among a,b,c or d that best fits the blank space in the following passage

During their five-decade history , the Asian Games have been advancing in all aspects . The number of (1)............. has been increasing . The quality of athletes , officials and sport facilities has also been (2)........................... through time . New sport and (3)............. sports have been introduced and (4)......... to the Games . The 1^st Asian Games (5)................. in New Delhi , India in 1951

1/ A. referees B. organizers C. participants D. holders

2/ A. developing B. raising C. falling D. pushing

3/ A. young B. strong C. advanced D. traditional

4/ A. multiplied B. added C. used D. bought

5/ A. held B. holding C. were held D. were holding

Choose the word or phrase among a,b,c or d that best fits the blank space in the following passage

About twenty percent of the world's present energy comes from the sun in one form or another . Special devices have already been made available to put on the roofs of houses and flats to cath the sun's rays and thus heat water . Thousands (1).................. these devices are now being used to provide (2)................. in homes throughout the United States while more (3)............ a million solar water-heating units have already been built in homes in Japan . Other purposes for which (4)................ energy is , at present , being used include the separation of salt from seawater , irrigation and sewage disposal

For most people in developing countries , the need is not for air - conditioners or central heating but for cheap (5)................. of cooking food , drying crops , and lighting houses

1/ A. in B. with C. on D. of

2/ A. light B. energy C. life D. existence

3/ A. than B. of C. through D. over

4/ A. sun B. sky C. space D. solar

5/ A. manners B. ways C. models D. types

Choose the word or phrase among a,b,c or d that best fits the blank space in the following passage

The Asian games , also (1)...................... the Asiad , are held every four years among (2).......... from all over Asia . The games are regulated (3).......... the Olympic Council of Asia (OCA) . Medals are (4).............. in each event , with gold for the first place , silver for the second and bronze for the third . The 15^th Asian Games were (5).................... in Doha , Qatar from December 1 to December 15,2006 . The 16^th Asian Games will be held in Guangzhou , China from November 12, 2010 to November 27 , 2010

1/ A. known B. named C. called D. thought

2/ A. people B. athletes C. athletics D. runners

3/ A. with B. through C. under D. by

4/ A. received B. awarded C. given D. won

5/ A. held B. take place C. organized D. happened

Choose the word or phrase among a,b,c or d that best fits the blank space in the following passage

Coin collecting is one of the most important hobbies in the world . Most coin (1)......... simply enjoy trying to acquire a complete set of a nation's coin . Some people collect coins as work of art . (2)............ collect them as an investment , to be sold later at a profit . Through coins , a collector can also (3)........... something about certain famous people and events in a country's (4)................ . Imaginative coin collectors can build many types (5)........... collection

1: A. collecting B. collection C. collected D. collectors

2: A. The other B. Others C. Another D. Other

3: A. offer B. learn C. give D. teach

4: A. geography B. nature C. history D. science

5: A. of B. in C. for D. on

Rewrite the sentences to focus attention on the underlined information . Using structure "it is /was.. that "

1. My secretary sent the bill to Mr.Harding yesterday (gạch chân the bill )

................................................................................................................................................................

2. We are coming to stay with Jane this weekend ( gạch chân this weekend )

................................................................................................................................................................

3. The president makes the important decisions ( gạch chân the important decisions )

................................................................................................................................................................

4. I'm looking forward to physics exam ( gạch chân physics exam )

...........................................................................................................................................................

5. My teacher helped me a lot of with my study last semester ( gạch chân my teacher )

..................................................................................................................................................................

6. The headmaster gave Tam a bicycle as a scholarship ( gạch chân Tam )

.....................................................................................................................................................................

VIẾT LẠI CÂU

1. We can't leave if Johns doesn't drive ( until )

We'll ........................................................................................

2. That old keyboard is not worth repairing ( pointless )

It is ...................................................................................

3. Reus has improved a lot this term

Reus ................................................................................

4. "Don't break the doll , John , or I'll scream , " said Mary

Mary threatened .........................................................................

5. Can you describe him to me ?

What ........................................................ ?

6. I live far from my bf . I miss him very much

The father .................................................................

7. Is it true that you haven't found a job yet ?

Are you still ................................................. ?

8. You can talk all you want , but I never believe you

Nothing you say ............................................................

9. Rita doesn't realize how serious her husband's operation is going to be

Little .......................................................................................................

10. Driving at that speed is dangerous on this road , whether you are an experienced driver or not

However ...................................................................................................................................

11. No decision in the issue has been made yet

Nothing .............................................................

12. One of my favorite pastimes is watching plays

Going .................................................................

13. The deer doesn't eat meat and hippotamus doesn't eat meat either

Neither .......................................................................................................

14. We can't start the meeting until John comes

Not until ...................................................................

15. "Viet, I'm sorry I broke you heart "

Lan apologized .........................................................

16. The owners of restaurants are usually rich

The people ......................................................

17. These two boxes weigh exactly the same

There is no .................................................................

18. Long and his family went on a trip to their home village for 2 days

Long and his family ...................................................................................

19. You should make an effort to get out and about more

It's high time ..........................................................................

20. A country cannot be prosperous if it is not quite independent

Only ...........................................................................................

21. People say that he can speak 4 or 5 foreign languages

He ...................................................................................

22. She had completely forgotten him ( mind )

....................................................................................

23. My friend took no notice of my advice ( deaf )

....................................................................................

24. Thiago knew that he had no chance to get a driving license as it was too hard for him ( wind )

......................................................................................................................................................................

25. Having to tell her about that terrible news , he couldn't make himself to do it ( face )

.......................................................................................................................................

26. The box of candy was passed from one person to another ( hand )

................................................................................................................

27. It's impossible for us not to laugh when he starts singing

We can't .......................................................................................

28. They say Tom has been offered that job

Tom is ..................................................................................

29. You can't answer the question if you haven't read the book

Only when ...............................................................................................

30. Smoking in the library is against the rules

You are ..............................................................................

31. Nothing was done about it

Nobody ...........................................................................................

32. To be the best of my knowledge , Messi is the most footballer in the world

As far ............................................................................................................

33. I'm certainly not going to give you any more money

I have no ...................................................................................

34. You have disobeyed ; you will therfore be punished

As a result .............................................................................................

35. His real identity will always remain a secret

No one .....................................................................................

36. I had only just put the phone down when the boss rang back

Hardly ..................................................................................................

37. The manager is not to be disturbed

On no account ......................................................................

38. She said she thought Tom was a liar

She accused ...........................................................................................

39. It's against the rules to touch the ball with your hand

You are not ...................................................................................

40. Who is the owner of this modern house ?

Who does ............................................................................

41. Their knowledge of music is very limitted

They don't ...................................................................

42. Hitch-hiking is less popular now than 10 years ago ( not )

Hitch-hiking is ................................................................................

43. I am not strong enough to climb that steep path withou a walking stick ( too )

......................................................................................................................................

44. I think the concert will probably not take place ( highly )

I think it's ................................................... the concert will take place

45. Make sure you wear clothes that don't restrict your movements ( allow )

Make sure you wear clothes .............................................. freely

46. You don't have to pay to go into that museum ( get )

You can ............................................ free

47. I thought his behavior was very silly ( behaved )

I thought he ................................................... way

48. Not many students attended EXO's concert ( number )

Only .......................... students attended EXO's concert

49. Manse is heavier than he was two years ago ( put )

Manse ................................................... in the last two years

50. She had no intention of insulting you ( mean )

She ....................................................................... you

51. I have no objection to Paul coming as well ( mind )

I do ................................................................. as well

52. This old car probably won't last for more than a year ( unlikely )

This old car .................................................. for more than a year

53. Taylor will not buy that dress because she is no longer interested ( lost )

Taylor ......................................................................... buying that dress

54. Buying cheap equipment is not worth the money (waste )

It's a ........................................................ buying cheap equipment

THE END .

Hỗn hợp X chứa glixerol và một ancol no đơn chức A

- Cho 20,3 gam A tác dụng với Na lấy dư thu được 5,04 lít H₂ (đktc)

- Mặt khác 8,12 gam X hòa tan vừa hết 1,96 gam Cu(OH)₂

Xác định công thức phân tử , các công thức cấu tạo có thể có , tên và phần trăm về khối lượng của ancol đơn chức trong hỗn hợp A .