Cho tam giác ABC cân tại A nội tiếp trong đường tròn (O) các đường cao AG, BE, CF cắt nhau tại H : a) Vẽ hình b) Chứng minh tứ giác AEHF nội tiếp. Xác định tâm (I) của đường tròn ngoại tiếp tứ giác đó. c) Chứng minh AE . AC = AH . AG
Một người đi xe đạp xuất phát từ A. Sau 4 giờ một người đi xe máy cũng đi từ A và đuổi theo trên cùng một con đường và gặp người đi xe đạp cách A là 60 km. Tính vận tốc của mỗi người. Biết vận tốc của người đi xe máy lớn hơn vận tốc của người đi xe đạp là 20 km/h.
Viết đoạn văn nêu suy nghĩ của bản thân về Bác Hồ kính yêu: - Suy nghĩ về con người Hồ Chí Minh. - Suy nghĩ về lối sống giản dị và thanh cao của Bác. - Suy nghĩ về tấm gương đạo đức Hồ Chí Minh…
56 phút trước
Find a mistake (0,4 pt)31. My motorbike runs on electricity. How about your? A B C Dyours 32. Its about two women living on different countries and they decide to exchange houses. A B in C D Rewrite sentences without changing meanings. (0,4 pt)33. We couldnt win the match although we played well. -- We played 34. Whats th...
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Find a mistake (0,4 pt)
31. My motorbike runs on electricity. How about your?
A B C Dyours
32. It's about two women living on different countries and they decide to exchange houses.
A B in C D
Rewrite sentences without changing meanings. (0,4 pt)
33. We couldn't win the match although we played well.
-- We played
34. What's the distance between HCM City and Ha Noi?
-- How
35. Are you interested in watching action movie or romantic movie?
Do you __________________________________________________________________?
36. It is about 32 kilometres from Vinh Long City to Can Tho City.
The distance________________________________________________________
Hai số hạng đầu tiên của khai triển \(\left(1+0,04\right)^n\) là:
\(C_n^0.1^n.0,04^0+C_n^1.1^{n-1}.0,04^1=1+0,04n\)
Vậy sau n năm thì dân số tỉnh đó xấp xỉ: \(1,8\left(1+0,04n\right)\) triệu người
\(\Rightarrow1,8.\left(1+0,04n\right)=2,2\)
\(\Rightarrow n\approx5,56\) năm
Làm tròn lên là 6 năm
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1 giờ trước (11:54)
REVISION 2 FOR THE 2ND SEMESTER EXAMI. Listen and choose the best answer. (1.0 pt)1. Power stations use fossil fuels like _______ to produce electricity. A. coal, oil and gas B. coal and gas C. oil and gas2. Burning fossil fuels produces _______ which cause global warming. A. greenhouse gases B. carbon dioxide C. methane3. We can use the _______ to make electricity. A. sun and water B. sun and wind C. sun, wind and water4. The ren...
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REVISION 2 FOR THE 2ND SEMESTER EXAM
I. Listen and choose the best answer. (1.0 pt)
1. Power stations use fossil fuels like _______ to produce electricity.
A. coal, oil and gas B. coal and gas C. oil and gas
2. Burning fossil fuels produces _______ which cause global warming.
A. greenhouse gases B. carbon dioxide C. methane
3. We can use the _______ to make electricity.
A. sun and water B. sun and wind C. sun, wind and water
4. The renewable sources can be used again and again because they ______ .
A. can run out B. cannot run out C. should run out
5. Renewable sources are _______ harmful to the environment.
A. much more B. much less C. not less
II. Listen and choose True or False. (1.0 pt)
___ 6. According to the survey, young and inexperienced drivers are the most likely to have an accident.
___ 7. Generally, older men are likely to drive fast cars with big engines.
___ 8. Passengers have an effect on the driver.
___ 9. When men have their wives or girlfriends in the car, they drive worse.
___ 10. When children are in the car, mothers drive more slowly and safely.
Read the passage carefully and choose A, B, C, or D to fill in the blanks. (1.0 pt)
When you are in Singapore, you can go about (11)_____ taxi, by bus, or by underground. I myself prefer the underground because it is fast, easy and cheap. There are (12)______ buses and taxis in Singapore and one cannot drive along the road quickly and without many stops, especially on Monday morning. The underground is therefore usually quicker (13)______ taxis or buses. If you do not know Singapore very well, it is difficult to find the bus you want. You can take a taxi, but it is (14)______ expensive than the underground or a bus. (15)______ the underground, you find good maps that tell you the names of the stations and show you how to get to them, so it is easy to find your way.
11. A. by B. in C. at D. on
12. A. few B. a lot C. many D. some
13. A. so B. like C. than D. as
14. A. less B. more C. most D. much
15. A. On B. In C. At D. By
Read the passage carefully and choose the best answers. (1.0 pt)
My first visit to the cinema was a very unhappy one. I was taken there by some friends when I was only seven years old. At first there were bright lights and music and I felt quite happy. When the lights went out, I felt afraid. Then I saw a train on the screen. The train was coming towards me. I shouted out in fear and got down under my seat. When friends saw me, they started to laugh. I felt ashamed and sat back in my seat. I was very glad when the film ended.
16. Who took the writer to the cinema for the first time?
A. His father B. His parents C. His friends D. His parents’ friends
17. How did he feel at first?
A. excited B. unhappy C. sad D. quite unhappy
18. He was frightened when _______.
A. there was music B. the lights went out
C. the train ran D. his friends saw him
19. Where did he hide when he saw the train coming towards him?
A. under the seat B. on the screen
C. on his friends’ back D. under the train seat
20. How did he feel before the film finished?
A. very glad B. very happy C. quite happy D. quite ashamed
Choose the word whose underlined part is pronounced differently from the others
21. A. plane B. traffic C. passenger D. narrow
Choose the word which has the syllable stressed differently from the others
22. A. dangerous B. government C. energy D. resources
Choose the best answer
23. You _______ look right and left when you go across the road.
A. can’t B. can C. shouldn’t D. should
24. The film was exciting; _______, Tom fell asleep in the cinema.
A. But B. Although C. However D. So
25. He _______ round the lake near his house at the moment.
A. cycled B. is cycling C. will cycle D. cycles
26. “How did she get here?” - “________”
A. She came by train. B. She came here last night.
C. The train was crowded. D. Is it far from here?
27. Traffic accidents can be prevented if people ________ the rules.
A. remember B. obey C. go after D. take care of
28. I think you will enjoy Our Holiday. It's quite _______.
A. enjoyable B. enjoy C. enjoyably D. enjoyment
29. The public ________ in this city is quite good, and it’s not expensive.
A. journey B. travel C. vehicle D. transport
30. When energy comes from ________, we call it hydro energy.
A. wind B. water C. sun D. nuclear
Cho hình lăng trụ tam giác đều ABC.A'B'C' có cạnh đáy bằng a, cạnh bên AA'=3a/2. Tính theo a
a) Khoảng cách từ điểm A đến mặt phẳng (A'BC)
b) Khoảng cách từ trung điểm M của CC' đến mặt phẳng (A'BC)
a.
Gọi D là trung điểm BC, từ A kẻ \(AE\perp A'D\)
\(\Rightarrow AD\perp BC\)
\(A'A\perp\left(ABC\right)\Rightarrow A'A\perp BC\)
\(\Rightarrow BC\perp\left(A'AD\right)\Rightarrow BC\perp AE\)
\(\Rightarrow AE\perp\left(A'BC\right)\Rightarrow AE=d\left(A;\left(A'BC\right)\right)\)
\(AD=\dfrac{a\sqrt{3}}{2}\) (trung tuyến tam giác đều)
Hệ thức lượng: \(AE=\dfrac{A'A.AD}{\sqrt{A'A^2+AD^2}}=\dfrac{3a}{4}\)
b.
Gọi F là giao điểm AC' và A'C. Do ACC'A' là hình chữ nhật \(\Rightarrow O\) là trung điểm AC'
\(\Rightarrow OA=OC'\)
Ta có: \(\left\{{}\begin{matrix}C'M\cap\left(A'BC\right)=C\\C'C=2MC\end{matrix}\right.\) \(\Rightarrow d\left(M;\left(A'BC\right)\right)=\dfrac{1}{2}d\left(C';\left(A'BC\right)\right)\)
Lại có: \(\left\{{}\begin{matrix}AC'\cap\left(A'BC\right)=O\\OA=OC'\end{matrix}\right.\) \(\Rightarrow d\left(A;\left(A'BC\right)\right)=d\left(C';\left(A'BC\right)\right)\)
\(\Rightarrow d\left(M;\left(A'BC\right)\right)=\dfrac{1}{2}d\left(A;\left(A'BC\right)\right)=\dfrac{3a}{8}\)
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1 giờ trước (11:51)
IV. WRITING: (2,0 pts) * Task 1: Choose the words or phrases that are not correct (0,4pt)31. A lot of cultural and artist activities are held in Dalat Flower Festival. A B C D 32. What do people celebrate New Year around the world? A B C D * Task 2: Complete the second sentence so that it has a similar meaning to the first: (0.4 pt) 33...
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IV. WRITING: (2,0 pts)
* Task 1: Choose the words or phrases that are not correct (0,4pt)
31. A lot of cultural and artist activities are held in Dalat Flower Festival.
A B C D
32. What do people celebrate New Year around the world?
A B C D
* Task 2: Complete the second sentence so that it has a similar meaning to the first: (0.4 pt)
33. Are you interested in watching action movie or romantic movie?
Do you __________________?
34. It is about 32 kilometres from Vinh Long City to Can Tho City.
The distance ____________.
* Task 3: Write a paragraph (70-90 words) about the traffic accident in Vietnam, using this information.
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