Cho vật dao động đh x=10cos(4pi×t-pi/6)cm Xác định thời điểm vật tới biên âm lần thứ 5.

Giải hộ e bài này với ạ Em cảm ơn nhiều

6. After working on computers for long hours, you should ……… your eyes and relax. A. sleep B. sleep in C. wake D. rest 7. Rob eats a lot of fast food and he ……… on a lot of weight. A. takes B. puts C. spends D. brings 8. We need to spend less time ……… computer games. A. play B. to play C. playing D. to playing 9. The first working product that uses a design is called a ………. A. method B. technology C. redesign D. prototype 10. To ……… healthy, you need between 1,600 and 2,500 calories. A. let B. stay C. make D. do 11. I ate too much seafood, so I had a/an ……… yesterday. A. earache B. backache C. stomachache D. headache 12. Laughing is very good ………. your health. A. for B. of C. at D. to 13. When you have a fever, you should drink more water, stay in bed and relax ………. A. much B. more C. most D. less 14. After you test a prototype, you communicate information to other people. This information is called ……… A. hypothesis B. the results C. a story D. an investigation 15. The doctor advised him to play more sports and ……… computer games. A. more B. little C. less D. least

chứng minh tổng các góc A,B,C của tam giác ABC = 180 độ help mình nhá sắp nộp !!

Part 2. Questions 66 – 75 (2.0 points - 0.2/ each) Read the passage below and choose the best answer to each question. Today we take electricity for granted and perhaps we do not realize just how useful this discovery has been. Steam was the first invention that replaced wind power. It was used to drive engines and was passed through pipes and radiators to warm rooms. Petrol mixed with air was the next invention that provided power. Exploded in a cylinder, it drove a motor engine. Beyond these simple and direct uses, those forms have not much adaptability. On the other hand, we make use of electricity in thousands of ways. From the powerful voltages that drive our electric trains to the tiny current needed to work a simple calculator, and from the huge electric magnet in steel works that can lift 10 tons to the tiny electric magnet in a doorbell, all are powered by electricity. An electric current can be made with equal ease to heat a huge mass of molten metal in a furnace, or to boil a jug for a cup of coffee. Other than atomic energy, which has not as yet been harnessed to the full, electricity is the greatest power in the world. It is flexible, and so adaptable for any task for which it is wanted. It travels so easily and with incredible speed along wires and conductors that it can be supplied instantly over vast distances. To generate electricity, huge turbines or generators must be turned. In Australia they use coal or water to drive this machinery. When dams are built, falling water is used to drive the turbines without polluting the atmosphere with smoke from coal. Atomic power is used in several countries but there is always the fear of an accident. A tragedy once occurred at Chernobyl, in Ukraine, at an atomic power plant used to make electricity. The reactor leaked, which caused many deaths through radiation. Now scientists are examining new ways of creating electricity without harmful effects to the environment. They may harness the tides as they flow in and out of bays. Most importantly, they hope to trap sunlight more efficiently. We do not use solar heaters for swimming pools but as yet improvement in the capacity of the solar cells to create more current is necessary. When this happens, electric cars will be viable and the world will rid itself of the toxic gases given off by trucks and cars that burn fossil fuels. 66. The author mentions the sources of energy such as wind, steam, petrol in the first paragraph to________. A. suggest that electricity should be alternated with safer sources of energy. B. emphasize the usefulness and adaptability of electricity. C. imply that electricity is not the only useful source of energy. D. discuss which source of energy can be a suitable alternative to electricity. 67. Before electricity, what was sometimes passed through pipes to heat rooms? A. Gas B. Petrol C. Steam D. Hot wind 68. What does the author mean by saying that electricity is flexible? A. It is cheap and easy to use B. It is used to drive motor engines C. It can be adapted to various uses D. It can be made with ease 69. What do we call machines that make electricity? A. Voltages B. Electric magnets C. Generators or Turbines D. Pipes and radiators 70. The main forms of power used to generate electricity in Australia are ________. A. atomic power and water B. water and coal C. sunlight and wind power D. wind and gas 71. The word “they” in the last paragraph refers to ________. A. harmful effects B. the tides C. scientists D. new ways 72. Electric magnets are used in steel works to ________. A. lift heavy weights up to ten tons B. test the steel for strength C. heat the molten steel D. boil a jug of water 73. The advantage of harnessing the power of the tides and of sunlight to generate electricity is that they ________. A. do not pollute the environment B. are more reliable C. are more adaptable D. do not require attention 74. Which of the following power sources causes pollution by emitting harmful gases? A. Sunlight B. Petrol C. Water D. Wind 75. The best title for this passage could be ________. A. Types of Power Plants B. Electricity: Harmful Effects on Our Life C. How to Produce Electricity D. Why Electricity is So Remarkable

Xác định giá trị của x √1/x-1 Mọi người giúp em với

Ai giúp mình với Chú ý : dấu này : là dấu chia nha Còn cái kia là 4 nhân X Mình cân gấp

Part 1: Questions from 16 to 35. (3.0 points - 0.15/ each) Choose the best answer to each question. 16. I had two copies of it originally, but I can’t find ________ one now. A. another B. the other C. the others D. other 17. Professor Moore doesn’t work at the school ________. A. also B. too C. still D. any more 18. If only he ________me a chance, I could have told him the truth. A. could B. has given C. had given D. gave 19. The Chief of police, ________work is very important, takes care of the public safety. A. who B. whom C. whose D. which 20. She is wearing a ________. A. short nice nylon skirt B. nice short nylon skirt C. nylon short nice skirt D. nylon nice short skirt 21. To get touch with someone is ________. A. to touch him B. criticize C. respect him D. communicate with him 22. The ________ items in the cake are flour, sugar and shortening. A. alternative B. enviable C. commercial D. essential 23. I hung the picture ________ the fireplace. A. on B. under C. between D. above 24. Older people rarely approve ________ habits of the youngr generation. A. for B. to C. of D. with 25. She had changed so much that ________ anyone recognized her. A. almost B. hardly C. never D. no 26. The teacher was not invited. She ________ come, otherwise. A. will B. would C. would have D. had 27. Please go to the ________ to look for your hand luggage. A. lost and found B. barber’s C. butcher’s D. grocer’s 28. He’d better look for a different job, ________ he? A. shouldn’t B. hadn’t C. better not D. wouldn’t 29. ________ traveling is educational, it can also be stressful and expensive. A. Since B. Providing C. While D. Even 30. She insisted that the report ________ as his source of information. A. not be mentioned B. not to mention C. not mentioning D. not mention 31. Don't count your________ before they hatched. A. ducklings B. chickens C. puppies D. birds 32. The day their first child was bom, the new parents were ________ with joy. A. overpowered B. overtaken C. overcome D. overthrow 33. By the time you finish your job, everyone ________ home. A. has gone B. will have gone C. had gone D. was going 34. The ________ child is forever asking questions. He's incredibly curious. A. acquisitive B. acquitted C. inquisitive D. exquisite 35. ________, he couldn't solve that mathematical puzzle. A. As intelligent as was he B. Intelligent as he was C. So intelligent was he D. Although he is intelligent Part 2: Questions from 36 to 45. (2 points - 0.2/ each) Use the correct form of the word in brackets to complete each sentence. 36. All the dancers performed …………………..………….. (attract) 37. It is …………………..…………. to live in the country than in the city. (health) 38. Farmers have to use …………………..…………. to protect their crops. (herb) 39. He is a …………………..…………. scientist although he is still young. (know) 40. The …………………..…………. his father created in him helps him to be a good doctor. (inspire) 41. Those remote areas are still …………………..…………. to the Internet. (access) 42. He made quite a number of …………………..…………. in his career as a footballer. (succeed) 43. The …………………..…………. of knowledge for the young is a policy to follow. (rich) 44. No …………………..…………. details about the celebration have been given. (far) 45. Would you like to go …………………..…………. with us this Sunday? (picnic) Part 3: Questions from 46 to 50. (1 points - 0.2/ each) Each of the following sentences has an error. Find the errors and correct them. 46. Most people are surprising to see how rapidly bacteria can multiply under favorable conditions. 47. Little land animals live in the polar regions which covered with snow years round. 48. A dolphin, often called a “porpoise”, is considered to be one of the bright among animals. 49. It looks as if those kids can never keep quietly for just a while. 50. We found an interesting piece of furnitures in that old house we bought. Part 4: Questions from 51 to 55. (1 point - 0.2/ each) Fill in each blank with a suitable preposition. 51. Don’t look down …………………..Peter just because he’s not as good at the job as you are. 52. Could you slow ………………….., please. I don’t like driving so fast on country roads. 53. Our car broke …………………..at the side of the highway in the snowstorm. 54. She ran in a marathon last week but dropped …………………..after ten kilometers. 55. Billy hasn't been working; he won't get …………………..his examinations.

List 5 countries you know. What country do you like best? why?

tìm gtnn của biểu thức biết x>9 ạ $\frac{x+7}{√x -3}$ -3 ngoài dâu căn nha các bạn UwU